When I save a Photoshop file as a PNG, I have the option of "interlaced" or "no interlaced". When should I choose the former? And when should I choose the latter?
I would not use Interlaced at all. Interlaced used to be useful in the old days of no broadband and very slow dial-up connections (like 28K or less), but I don't see any need for it's use these days.