i’m not too keen on the difference between .jpg and .JPEG…
but why does blender only allow saving in .JPEG format, which doesn’t seem to be very web friendly?
i’m trying to make a 3DNP file, it should be 142 single .jpg frames.
should i learn to write a batch conversion script in GIMP for this, or will the sequencer be able to do it?
They are one and the same. You’re more likely to see .jpg as the file extension because of hysterical raisins.
Just select jpeg as your output format, and when you save the file give it a .jpg extension (as you have to supply the extension anyway).
Hope this helps.
[edit]You know, you’re better off saving frames in a lossless format, like PNG. When it’s time to encode the movie (AVI or MOV) is when to apply lossy compression.[/edit]
Duoas, thank you for clearing that up. hysterical raisins can be confusing little buggers sometimes 
I’ve got a question on this subject. After you render as seperate images for each frame, how do you recomposite them as a movie?
Don’t underestimate Blender’s sequence editor…
Open the sequence editor, Shift+A->Images, RMB on the first image, drag down to the last one and let go, click “Load images”, place the strip, turn on “Do Sequence” and render.
I didn’t know virtual dub did that! I use it for converting my mini dv movies to a form blender can use but I didn’t know it would sequence images.
On the blender sequence editor…Thank you, thank you, thank you! That’s what I’ve been looking for. Now I can do some serious rotoscoping! Oh boy hours of fun!
Blender’s sequence editor is actually very powerful, and underappreciated. The blender documentation is fairly curt on its use, but provides enough information to begin doing some amazing effects.
Also
http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Sequencer_Getting_Started
http://www.weirdhat.com/blender/compositing2/
Hmm, there was a very good topic posted about a year and a half ago that spoke about the sequence editor in general terms, but I can’t find it now…