Its funny, always stucks on 90% till it fails with the error that another big image may be keeping the server busy.

I mean ok its a "demo" tho the funny thing is if you actually check the cli and requests, you clearly can see that the 3 stages the images walks through on "processing" are fake, its just doing 1 post request in the backend that runs while it traverses through the states, and at 90% it stops until (in theory) the request ends.

When I saw the progress bar moving so smoothly I knew it was BS lol

Oh it's an IE6 progress bar then.