blueimp-load-image
Advanced tools
JavaScript Load Image is a library to load images provided as File or Blob objects or via URL. It returns an optionally scaled, cropped or rotated HTML img or canvas element. It also provides methods to parse image metadata to extract IPTC and Exif tags a
The blueimp-load-image npm package is a JavaScript library that provides functionality for loading and manipulating image files in the browser. It supports features such as image resizing, orientation correction, and metadata parsing, making it useful for web applications that handle image uploads and processing.
Load Image
This feature allows you to load an image from a file or URL and append it to the document body. The `maxWidth` option resizes the image to a maximum width of 600 pixels.
const loadImage = require('blueimp-load-image');
loadImage(
fileOrUrl,
function (img) {
document.body.appendChild(img);
},
{ maxWidth: 600 }
);Parse Image Metadata
This feature parses the metadata of an image file, such as EXIF data. The parsed metadata is logged to the console.
const loadImage = require('blueimp-load-image');
loadImage.parseMetaData(file, function (data) {
console.log(data.exif);
});Correct Image Orientation
This feature corrects the orientation of an image based on its EXIF data. The corrected image is then appended to the document body.
const loadImage = require('blueimp-load-image');
loadImage(
fileOrUrl,
function (img) {
document.body.appendChild(img);
},
{ orientation: true }
);Pica is a high-quality image resizing library that works in the browser. It focuses on providing fast and high-quality image resizing, making it a good alternative to blueimp-load-image for applications that require efficient image resizing.
Browser-image-compression is a library for compressing images in the browser. It provides functionality for reducing the file size of images while maintaining quality, which can be useful for web applications that need to handle large image uploads.
Exif-js is a JavaScript library for reading EXIF metadata from image files. It is a lightweight alternative to blueimp-load-image for applications that only need to extract and work with image metadata.
A JavaScript library to load and transform image files.
JavaScript Load Image is a library to load images provided as File or Blob
objects or via URL. It returns an optionally scaled, cropped or
rotated HTML img or canvas element.
It also provides methods to parse image metadata to extract IPTC and Exif tags as well as embedded thumbnail images, to overwrite the Exif Orientation value and to restore the complete image header after resizing.
Install via NPM:
npm install blueimp-load-image
Include the (combined and minified) JavaScript Load Image script in your HTML markup:
<script src="js/load-image.all.min.js"></script>
Or alternatively, choose which components you want to include:
<script src="js/load-image.js"></script>
<script src="js/load-image-scale.js"></script>
<script src="js/load-image-meta.js"></script>
<script src="js/load-image-fetch.js"></script>
<script src="js/load-image-orientation.js"></script>
<script src="js/load-image-exif.js"></script>
<script src="js/load-image-exif-map.js"></script>
<script src="js/load-image-iptc.js"></script>
<script src="js/load-image-iptc-map.js"></script>
In your application code, use the loadImage() function like this:
document.getElementById('file-input').onchange = function (e) {
loadImage(
e.target.files[0],
function (img) {
document.body.appendChild(img)
},
{ maxWidth: 600 } // Options
)
}
Or using the Promise based API like this:
document.getElementById('file-input').onchange = function (e) {
loadImage(e.target.files[0], { maxWidth: 600 }).then(function (data) {
document.body.appendChild(data.image)
})
}
It is also possible to use the image scaling functionality directly with an existing image:
var scaledImage = loadImage.scale(
img, // img or canvas element
{ maxWidth: 600 }
)
The JavaScript Load Image library has zero dependencies, but benefits from the following two polyfills:
Blob objects out of transformed canvas elements.loadImage API in Browsers without native Promise support.The loadImage() function accepts a
File or
Blob object or an image
URL as first argument.
If a File or
Blob is passed as
parameter, it returns an HTML img element if the browser supports the
URL API, alternatively a
FileReader object
if the FileReader API is supported, or false.
It always returns an HTML img element when passing an image URL:
var loadingImage = loadImage(
'https://example.org/image.png',
function (img) {
document.body.appendChild(img)
},
{ maxWidth: 600 }
)
The img element or
FileReader object
returned by the loadImage() function allows to cancel event handling by
setting the onload and onerror event handlers to null:
var loadingImage = loadImage(
'https://example.org/image.png',
function (img) {
document.body.appendChild(img)
},
{ maxWidth: 600 }
)
// Cancel event handling:
loadingImage.onload = loadingImage.onerror = null
For the callback style API, the second argument to loadImage() must be a
callback function, which is called when the image has been loaded or an error
occurred while loading the image.
The callback function is passed two arguments:
error.loadImage(
fileOrBlobOrUrl,
function (img, data) {
document.body.appendChild(img)
console.log('Original image width: ', data.originalWidth)
console.log('Original image height: ', data.originalHeight)
},
{ maxWidth: 600, meta: true }
)
Please note:
The original image dimensions reflect the natural width and height of the loaded
image before applying any transformation.
For consistent values across browsers, metadata parsing has
to be enabled via meta:true, so loadImage can detect automatic image
orientation and normalize the dimensions.
Example code implementing error handling:
loadImage(
fileOrBlobOrUrl,
function (img, data) {
if (img.type === 'error') {
console.error('Error loading image file')
} else {
document.body.appendChild(img)
}
},
{ maxWidth: 600 }
)
If the loadImage() function is called without a callback function as second
argument and the
Promise
API is available, it returns a Promise object:
loadImage(fileOrBlobOrUrl, { maxWidth: 600, meta: true })
.then(function (data) {
document.body.appendChild(data.image)
console.log('Original image width: ', data.originalWidth)
console.log('Original image height: ', data.originalHeight)
})
.catch(function (err) {
// Handling image loading errors
console.log(err)
})
The Promise resolves with an object with the following properties:
image: An HTML
img or
canvas element.originalWidth: The original width of the image.originalHeight: The original height of the image.Please also read the note about original image dimensions normalization in the callback arguments section.
If metadata has been parsed, additional properties might be present on the object.
If image loading fails, the Promise rejects with an
Event object of type
error.
The optional options argument to loadImage() allows to configure the image
loading.
It can be used the following way using the callback style:
loadImage(
fileOrBlobOrUrl,
function (img) {
document.body.appendChild(img)
},
{
maxWidth: 600,
maxHeight: 300,
minWidth: 100,
minHeight: 50,
canvas: true
}
)
Or the following way with the Promise based API:
loadImage(fileOrBlobOrUrl, {
maxWidth: 600,
maxHeight: 300,
minWidth: 100,
minHeight: 50,
canvas: true
}).then(function (data) {
document.body.appendChild(data.image)
})
All settings are optional. By default, the image is returned as HTML img
element without any image size restrictions.
Defines the maximum width of the img/canvas element.
Defines the maximum height of the img/canvas element.
Defines the minimum width of the img/canvas element.
Defines the minimum height of the img/canvas element.
The width of the sub-rectangle of the source image to draw into the destination
canvas.
Defaults to the source image width and requires canvas: true.
The height of the sub-rectangle of the source image to draw into the destination
canvas.
Defaults to the source image height and requires canvas: true.
The top margin of the sub-rectangle of the source image.
Defaults to 0 and requires canvas: true.
The right margin of the sub-rectangle of the source image.
Defaults to 0 and requires canvas: true.
The bottom margin of the sub-rectangle of the source image.
Defaults to 0 and requires canvas: true.
The left margin of the sub-rectangle of the source image.
Defaults to 0 and requires canvas: true.
Scales the image up/down to contain it in the max dimensions if set to true.
This emulates the CSS feature
background-image: contain.
Scales the image up/down to cover the max dimensions with the image dimensions
if set to true.
This emulates the CSS feature
background-image: cover.
Crops the image to the given aspect ratio (e.g. 16/9).
Setting the aspectRatio also enables the crop option.
Defines the ratio of the canvas pixels to the physical image pixels on the
screen.
Should be set to
window.devicePixelRatio
unless the scaled image is not rendered on screen.
Defaults to 1 and requires canvas: true.
Defines the ratio in which the image is downsampled (scaled down in steps).
By default, images are downsampled in one step.
With a ratio of 0.5, each step scales the image to half the size, before
reaching the target dimensions.
Requires canvas: true.
If set to false,
disables image smoothing.
Defaults to true and requires canvas: true.
Sets the
quality of image smoothing.
Possible values: 'low', 'medium', 'high'
Defaults to 'low' and requires canvas: true.
Crops the image to the maxWidth/maxHeight constraints if set to true.
Enabling the crop option also enables the canvas option.
Transform the canvas according to the specified Exif orientation, which can be
an integer in the range of 1 to 8 or the boolean value true.
When set to true, it will set the orientation value based on the EXIF data of
the image, which will be parsed automatically if the Exif extension is
available.
Exif orientation values to correctly display the letter F:
1 2
██████ ██████
██ ██
████ ████
██ ██
██ ██
3 4
██ ██
██ ██
████ ████
██ ██
██████ ██████
5 6
██████████ ██
██ ██ ██ ██
██ ██████████
7 8
██ ██████████
██ ██ ██ ██
██████████ ██
Setting orientation to true enables the canvas and meta options, unless
the browser supports automatic image orientation (see
browser support for image-orientation).
Setting orientation to 1 enables the canvas and meta options if the
browser does support automatic image orientation (to allow reset of the
orientation).
Setting orientation to an integer in the range of 2 to 8 always enables
the canvas option and also enables the meta option if the browser supports
automatic image orientation (again to allow reset).
Automatically parses the image metadata if set to true.
If metadata has been found, the data object passed as second argument to the callback function has additional properties (see metadata parsing).
If the file is given as URL and the browser supports the
fetch API or the
XHR
responseType
blob, fetches the file as Blob to be able to parse the metadata.
Returns the image as
canvas element if
set to true.
Sets the crossOrigin property on the img element for loading
CORS enabled images.
By default, the
created object URL
is revoked after the image has been loaded, except when this option is set to
true.
If the Load Image Meta extension is included, it is possible to parse image meta
data automatically with the meta option:
loadImage(
fileOrBlobOrUrl,
function (img, data) {
console.log('Original image head: ', data.imageHead)
console.log('Exif data: ', data.exif) // requires exif extension
console.log('IPTC data: ', data.iptc) // requires iptc extension
},
{ meta: true }
)
Or alternatively via loadImage.parseMetaData, which can be used with an
available File or Blob object as first argument:
loadImage.parseMetaData(
fileOrBlob,
function (data) {
console.log('Original image head: ', data.imageHead)
console.log('Exif data: ', data.exif) // requires exif extension
console.log('IPTC data: ', data.iptc) // requires iptc extension
},
{
maxMetaDataSize: 262144
}
)
Or using the Promise based API:
loadImage
.parseMetaData(fileOrBlob, {
maxMetaDataSize: 262144
})
.then(function (data) {
console.log('Original image head: ', data.imageHead)
console.log('Exif data: ', data.exif) // requires exif extension
console.log('IPTC data: ', data.iptc) // requires iptc extension
})
The Metadata extension adds additional options used for the parseMetaData
method:
maxMetaDataSize: Maximum number of bytes of metadata to parse.disableImageHead: Disable parsing the original image head.disableMetaDataParsers: Disable parsing metadata (image head only)Resized JPEG images can be combined with their original image head via
loadImage.replaceHead, which requires the resized image as Blob object as
first argument and an ArrayBuffer image head as second argument.
With callback style, the third argument must be a callback function, which is
called with the new Blob object:
loadImage(
fileOrBlobOrUrl,
function (img, data) {
if (data.imageHead) {
img.toBlob(function (blob) {
loadImage.replaceHead(blob, data.imageHead, function (newBlob) {
// do something with the new Blob object
})
}, 'image/jpeg')
}
},
{ meta: true, canvas: true, maxWidth: 800 }
)
Or using the Promise based API like this:
loadImage(fileOrBlobOrUrl, { meta: true, canvas: true, maxWidth: 800 })
.then(function (data) {
if (!data.imageHead) throw new Error('Could not parse image metadata')
return new Promise(function (resolve) {
data.image.toBlob(function (blob) {
data.blob = blob
resolve(data)
}, 'image/jpeg')
})
})
.then(function (data) {
return loadImage.replaceHead(data.blob, data.imageHead)
})
.then(function (blob) {
// do something with the new Blob object
})
.catch(function (err) {
console.error(err)
})
Please note:
Blob objects of resized images can be created via
canvas.toBlob.
blueimp-canvas-to-blob
provides a polyfill for browsers without native
canvas.toBlob
support.
If you include the Load Image Exif Parser extension, the argument passed to the
callback for parseMetaData will contain the following additional properties if
Exif data could be found in the given image:
exif: The parsed Exif tagsexifOffsets: The parsed Exif tag offsetsexifTiffOffset: TIFF header offset (used for offset pointers)exifLittleEndian: little endian order if true, big endian if falseThe exif object stores the parsed Exif tags:
var orientation = data.exif[0x0112] // Orientation
The exif and exifOffsets objects also provide a get() method to retrieve
the tag value/offset via the tag's mapped name:
var orientation = data.exif.get('Orientation')
var orientationOffset = data.exifOffsets.get('Orientation')
By default, only the following names are mapped:
OrientationThumbnail (see Exif Thumbnail)Exif (see Exif IFD)GPSInfo (see GPSInfo IFD)Interoperability (see Interoperability IFD)If you also include the Load Image Exif Map library, additional tag mappings become available, as well as three additional methods:
exif.getText()exif.getName()exif.getAll()var orientationText = data.exif.getText('Orientation') // e.g. right-top
var name = data.exif.getName(0x0112) // Orientation
// A map of all parsed tags with their mapped names/text as keys/values:
var allTags = data.exif.getAll()
Example code displaying a thumbnail image embedded into the Exif metadata:
loadImage(
fileOrBlobOrUrl,
function (img, data) {
var exif = data.exif
var thumbnail = exif && exif.get('Thumbnail')
var blob = thumbnail && thumbnail.get('Blob')
if (blob) {
loadImage(
blob,
function (thumbImage) {
document.body.appendChild(thumbImage)
},
{ orientation: exif.get('Orientation') }
)
}
},
{ meta: true }
)
Example code displaying data from the Exif IFD (Image File Directory) that contains Exif specified TIFF tags:
loadImage(
fileOrBlobOrUrl,
function (img, data) {
var exifIFD = data.exif && data.exif.get('Exif')
if (exifIFD) {
// Map of all Exif IFD tags with their mapped names/text as keys/values:
console.log(exifIFD.getAll())
// A specific Exif IFD tag value:
console.log(exifIFD.get('UserComment'))
}
},
{ meta: true }
)
Example code displaying data from the Exif IFD (Image File Directory) that contains GPS info:
loadImage(
fileOrBlobOrUrl,
function (img, data) {
var gpsInfo = data.exif && data.exif.get('GPSInfo')
if (gpsInfo) {
// Map of all GPSInfo tags with their mapped names/text as keys/values:
console.log(gpsInfo.getAll())
// A specific GPSInfo tag value:
console.log(gpsInfo.get('GPSLatitude'))
}
},
{ meta: true }
)
Example code displaying data from the Exif IFD (Image File Directory) that contains Interoperability data:
loadImage(
fileOrBlobOrUrl,
function (img, data) {
var interoperabilityData = data.exif && data.exif.get('Interoperability')
if (interoperabilityData) {
// The InteroperabilityIndex tag value:
console.log(interoperabilityData.get('InteroperabilityIndex'))
}
},
{ meta: true }
)
The Exif parser adds additional options:
disableExif: Disables Exif parsing when true.disableExifOffsets: Disables storing Exif tag offsets when true.includeExifTags: A map of Exif tags to include for parsing (includes all but
the excluded tags by default).excludeExifTags: A map of Exif tags to exclude from parsing (defaults to
exclude Exif MakerNote).An example parsing only Orientation, Thumbnail and ExifVersion tags:
loadImage.parseMetaData(
fileOrBlob,
function (data) {
console.log('Exif data: ', data.exif)
},
{
includeExifTags: {
0x0112: true, // Orientation
ifd1: {
0x0201: true, // JPEGInterchangeFormat (Thumbnail data offset)
0x0202: true // JPEGInterchangeFormatLength (Thumbnail data length)
},
0x8769: {
// ExifIFDPointer
0x9000: true // ExifVersion
}
}
}
)
An example excluding Exif MakerNote and GPSInfo:
loadImage.parseMetaData(
fileOrBlob,
function (data) {
console.log('Exif data: ', data.exif)
},
{
excludeExifTags: {
0x8769: {
// ExifIFDPointer
0x927c: true // MakerNote
},
0x8825: true // GPSInfoIFDPointer
}
}
)
The Exif parser extension also includes a minimal writer that allows to override
the Exif Orientation value in the parsed imageHead ArrayBuffer:
loadImage(
fileOrBlobOrUrl,
function (img, data) {
if (data.imageHead && data.exif) {
// Reset Exif Orientation data:
loadImage.writeExifData(data.imageHead, data, 'Orientation', 1)
img.toBlob(function (blob) {
loadImage.replaceHead(blob, data.imageHead, function (newBlob) {
// do something with newBlob
})
}, 'image/jpeg')
}
},
{ meta: true, orientation: true, canvas: true, maxWidth: 800 }
)
Please note:
The Exif writer relies on the Exif tag offsets being available as
data.exifOffsets property.
If you include the Load Image IPTC Parser extension, the argument passed to the
callback for parseMetaData will contain the following additional properties if
IPTC data could be found in the given image:
iptc: The parsed IPTC tagsiptcOffsets: The parsed IPTC tag offsetsThe iptc object stores the parsed IPTC tags:
var objectname = data.iptc[5]
The iptc and iptcOffsets objects also provide a get() method to retrieve
the tag value/offset via the tag's mapped name:
var objectname = data.iptc.get('ObjectName')
By default, only the following names are mapped:
ObjectNameIf you also include the Load Image IPTC Map library, additional tag mappings become available, as well as three additional methods:
iptc.getText()iptc.getName()iptc.getAll()var keywords = data.iptc.getText('Keywords') // e.g.: ['Weather','Sky']
var name = data.iptc.getName(5) // ObjectName
// A map of all parsed tags with their mapped names/text as keys/values:
var allTags = data.iptc.getAll()
The IPTC parser adds additional options:
disableIptc: Disables IPTC parsing when true.disableIptcOffsets: Disables storing IPTC tag offsets when true.includeIptcTags: A map of IPTC tags to include for parsing (includes all but
the excluded tags by default).excludeIptcTags: A map of IPTC tags to exclude from parsing (defaults to
exclude ObjectPreviewData).An example parsing only the ObjectName tag:
loadImage.parseMetaData(
fileOrBlob,
function (data) {
console.log('IPTC data: ', data.iptc)
},
{
includeIptcTags: {
5: true // ObjectName
}
}
)
An example excluding ApplicationRecordVersion and ObjectPreviewData:
loadImage.parseMetaData(
fileOrBlob,
function (data) {
console.log('IPTC data: ', data.iptc)
},
{
excludeIptcTags: {
0: true, // ApplicationRecordVersion
202: true // ObjectPreviewData
}
}
)
The JavaScript Load Image library is released under the MIT license.
FAQs
JavaScript Load Image is a library to load images provided as File or Blob objects or via URL. It returns an optionally scaled, cropped or rotated HTML img or canvas element. It also provides methods to parse image metadata to extract IPTC and Exif tags a
The npm package blueimp-load-image receives a total of 156,813 weekly downloads. As such, blueimp-load-image popularity was classified as popular.
We found that blueimp-load-image demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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