I'm having trouble making stickers.

[Jaco van der Molen]

There is a bug in 1.6b which prevents texture loading when filenames with spaces in them are used.

This is fixed in 1.6c but until that version is released you should prevent using spaces in the png name.

Other then that its best to keep the .png in the same folder as the .dat using it.

Yeah, that was part of the problem, because when I removed the spaces, it worked just fine... in LDCad... by itself. When I imported it into LeoCAD, the texture disappeared again! IDK why this is, and it's really getting frustrating... 

Sorry, I have no experience with LeoCAD and textures.
But I can asume you have to leave the png in the same folder for that like Roland said.
I didn't know better on how to work with patterned parts then I mentioned and putting the png in the textures folder.