This is looking okay, but the black areas really should be transparent:
Having edited the original nine normal JPGs into nine full-sized .PNG photos with transparent areas on each one, I decided to tile them (as seen on the above thumbnail), but realized that none of my many photo editors would deliver! Either they wouldn't offer to tile, or they would not maintain the transparency. It seems most can handle transparency if I edit the photos one by one, but not when I combine/group/tile the pictures.
So, do you know of a photo editor that will both combine/tile, and keep PNG transparency?
Edited:
please do not tell about some expensive solution ;-)