Image editor not retaining alpha from paint package

I'm using a paint package to make a small monochrome image (a tile) on a transparent background. It's fully transparent in the paint package and I've done this many times before. All I usually do is just copy it from the paint package into the clipboard and then paste it into the image editor, but it's arriving without the transparency. Any ideas what's causing this?

This has never worked in C3. You need to save the image in png and then load it into the animation editor.

For the record, it's a bug in Chrome.

Oh, thanks. I eventually just saved and loaded, that works fine as mentioned.