Photoshop as the only tool of trade ???
My first post here, great site/community :)
Anyways im so used to Photoshop(over 10 years) that i cant even imagine any other tool. Drawing lines in Illustrator is like operating a space rocket to me.
Are raster 4000x4000 pixel images big enough to be printed ? Threadless most likely accept only vector, but one day i want to print on shirts myself too.