The upload limit appears to be 4MB by default.
Despite that the largest image I can upload is 505kb (as a test user and under my main account)
I ran a test upload of 600kb and it hung at [Processing: megaduck-600kb.jpg...]()
More importantly there was no “Uploading” bar at the bottom, no errors in JS console or Network activity so I think something else is borking up the process and it’s probably? on the client-side.
It may be a tricky one to nail down.