Weirdly did not work in Firefox on Ubuntu. Switched to Chromium and got 1182 before deciding to quit. The framerate was pretty slow, which I think is the only reason I got > 1000. :)
The fiddle works in both Chromium and Firefox for me (a 16x16 green filled square), but the data URL produced by Firefox results in vertical line rainbow. In Chromium it works fine.
FF: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAQUlEQVQ4T2O83OR55grL9sMTZ1tdefydOU2t5o50tbH8dc+a8h8pYZ8fZ71cboZPnnHUgMejYfB5NAyAeWUYpAMAFY8jzzH0m5oAAAAASUVORK5CYII="
Chromium: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAAXNSR0IArs4c6QAAAB5JREFUOE9jZGhg+M9AAWAcNYBhNAwYRsOAYViEAQCDTRgBEA8acQAAAABJRU5ErkJggg=="
https://onlineimagetools.com/base64-decode-png can be used to quickly see if you're inclined.