JPEG vs PNG

[billfisher]

JPEG has lossy compression which throws away data the eye typically doesn't see (unless you really drop the quality slider!) assuming you're not viewing it up close or anything. Every print service in the world will take a JPEG. Bad if you're going to keep opening, modifying, and saving.

PNG has lossless compression, handles transparency, and all sorts of good stuff. Great for editing and re-editing (though you'll probably use psd to keep layers, etc.). You'd have to ask your print service if they support PNG, of if you need to do your final export as JPEG.

Thank you so much for the detailed explanation!