Image file size from data URI in JavaScript

Question

I am not sure it's even possible but - can I get the image file size from data URI?

For example, let's say there is an IMG element where src goes:

src="data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD...

Based on the src, can I get the image file size by using plain JavaScript? (without server request)

Answer 1

If you want file size, simply decode your base64 string and check the length.

var src ="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP/// yH5BAEAAAAALAAAAAABAAEAAAIBRAA7";

var base64str = src.substr(22);
var decoded = atob(base64str);

console.log("FileSize: " + decoded.length);