Newbie with this sort of problem again.
I have a pic that I want to superimpose on a target.
The pic is a png obtained on the web, described as having a transparent background. The target is a jpg obtained on the web. I resaved the target as a png, if that matters....
I open the target in paint.net.
I open the pic in another paint.net window. It shows a checkerboard background.
I select all and copy it.
I paste it in the target windows, on a new layer. It shows up with an apparently opaque checkerboard background.
What do I need to do to have the 'transparent' background be transparent, so I can see the target image except where the non-background image of the pic covers it, as I want?
