Martin Perry Martin Perry - 1 year ago 532
Javascript Question

HTML5 - resize image and keep EXIF in resized image

How can I resize an image (using an HTML5

element) and keep the EXIF information from the original image? I can extract EXIF info from from original image but I don't know how to copy it to the resized image.

This is how I retrieve the resized image data to send to the server-side code:

canvas.toDataURL("image/jpeg", 0.7);

For EXIF retrieval, I'm using the exif.js library.

Answer Source

Working solution: ExifRestorer.js

Usage with HTML5 image resize:

function dataURItoBlob(dataURI) 
    var binary = atob(dataURI.split(',')[1]);
    var array = [];
    for(var i = 0; i < binary.length; i++) {
    return new Blob([new Uint8Array(array)], {type: 'image/jpeg'});

And main code, taken as part of HTML5 resizer from this page: (but slightly modified)

var reader = new FileReader();

//reader.readAsArrayBuffer(file); //load data ... old version
reader.readAsDataURL(file);       //load data ... new version
reader.onload = function (event) {
// blob stuff
//var blob = new Blob([]); // create blob... old version
var blob = dataURItoBlob(; // create version
window.URL = window.URL || window.webkitURL;
var blobURL = window.URL.createObjectURL(blob); // and get it's URL

// helper Image object
var image = new Image();
image.src = blobURL;

image.onload = function() {

   // have to wait till it's loaded
   var resized = ResizeImage(image); // send it to canvas

   resized = ExifRestorer.restore(, resized);  //<= EXIF  

   var newinput = document.createElement("input");
   newinput.type = 'hidden'; = 'html5_images[]';
   newinput.value = resized; // put result from canvas into new hidden input
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