.TGA VS .PNG

Increasingly now on the SL forum we have people scratching their heads because they made PNG textures with (they think) no transparency but are having the OpenGL alpha-sorting issue that is common in our world of unoptimised builds.

TGA textures are either 24 or 32 bit, with the 32 bit supporting transparency. In cases where a texture is misguidedly or accidentally set to 32 bit, unnecessary battling with alpha-sorting is the outcome. Still, it's clear: 24 bit = no issues; 32 bit= issues to deal with.

PNG textures operate in a different way, which makes them w00tfully useful for lots of things but opens the door to head-scratching in SL as the difference between opaque-transparent is not cut and dried. If there is accidentally even one rotten old transparent pixel the entire image is reckoned to be transparent, and will alpha-sorting-glitch people until the cows come home.

For SL, targas rock. They are an awesome graphics filetype. For lots of other things .png files rock, but I'd say use targas unless you have a good reason not to.