Q:

How to increase performance in fabric. Image.fromURL

I am trying to load images from my canvas to fabric canvas using 
fabric. Image.fromURL(hc.toDataURL(), 
               function(img) {
                    canvas.add(img);
               }
 );

But if I add a 25 MB image it doesn't load the image at all. 
However without using fabric js I was able to do that by copying canvas and putImageData.  
Any suggestions on how to improve performance ? 

A:

hc i.e. hidden canvas will be a reference to actual fabric canvas. 
so, it totally depends on how you load your hidden canvas. 
So, probably try to fix that part before coming to fabric rendering part. 
Hope this clears.