Copy / Paste to Firefox thinks that the image is empty; works for Chrome
When I copy a scanned page and try to paste it to a browser (ex: this tool: https://pasteboard.co/), it works well with Chrome but not with Firefox. Firefox thinks that this image is empty.
I don't think it's a Firefox issue because pasting image from other source (Gimp, image open in browser) works well. So maybe something is incorrect in the copied data.
Using Fedora 30.
Possible duplicate of #85.