How To Covert JPGs to AVI or FLV?

I have a number of free AVI and FLV utilities (All Free Video Joiner, DVDvideoSoft Free Studio et al) but I don't see that any of them can convert a series of JPGs to AVI or FLV (what amounts to a slideshow). I then want to add an audio track to the end result. (FLV is what I need at the end but I have an AVI to FLV converter so I can use AVI as an intermediary format, if that is necessary.) Is there any free utility that will let me do that?

thank you.