export UI should be its own control panel, not be a bump on the side of import UI
show some indication that something is happening so i know it's working / about how long to expect it to take
UI should show the URL of exported image but also show the exported image itself (at small size?) with the message "right click & save as". Possibly also an HTML snippet "copy paste this to embed your image anywhere".
Also, after an export, the drawcanvas turns white and unresponsive and the tool canvas does too, although no error messages appear in the JS error console. The whole page has to be reloaded. What's going on there?