I cannot get Image Edit to work on mages made by Image

That changes the image from 24 bit to 32 bit, but doesn’t actually draw the transparency for you in the alpha channel of the image:

If mask is not provided, image must have transparency, which will be used as the mask.

The AI has to know where it is allowed to paint new stuff, and where it should leave the image unaltered.

Pixel transparency should be fully “on” or fully transparent, not fading as a photoshop erase tool does by default.

I offered gimp links in this similar topic: