Thanks, Both, but I have been misunderstood.
tailstrike - As a pretty serious amateur photographer since the dawn of time, and a digitial one for rather long too, I know very well that Jpeg is lossy.
I happen to shoot in Canon's .CR2 RAW format and then convert to Jpeg when I'm done for ease of viewing and to save storage space. Even then, I still keep the RAW files for important events.
bnt - Thanks, I will look at the software you suggest. Note though that I am NOT compressing
backup photos. Please re-read my post. I have a four level backup plan that involves a NAS (hidden in an outbuilding for the record) as well as off site rotation of the e-SATA and USB devices. My compression need is ONLY for ease of e-mailing (much easier to have an entire collection to hand, already compressed, than to do it per e-mail) and for speed of browsing with my wife's 802.11g netbook (full size originals take several seconds to load, making fast browsing impossible, whereas 100kb copies look just as good on the pixel-limited screen and load in a flash)