guess it depends on what you plan on doing after. If I plan on a 5 sec or so gif I do uncompressed avi, if I plan on edditing later I use what codecs my moive editing soft imports. Dunno if theres a speed dif in single frames over my way, single frames is a safer way if anything goes wrong u can recover from where it went wrong (sorta lol )

So find a way that suits you, your comp and the software you have  but most of all have fun