Comment on FireFox by lunalove101
I don't know what the problem is. What you're doing originally should work out. However, you still have to make sure that your original new file is transparent already. Then, you make another layer of white above it to see your sketch then erase it and save as a PNG. o:
When not using the 'color to alpha', I usually make a transparent layer as a background and draw on the layer above, unfortunately with the same results.
Huh.. I don't know what to tell you then.. You could always look up a tutorial here on dA.
I think that's what I'll do.