Everyone knows that there is only one way to prevent your images from being leeched online .... don't post at all.
But there is another way to "discourage" others from leeching is to post low-res photos, usually below 30k. Pic quality may not be good but still acceptable in most situations. Also, if you realise, most of the leeched images are mostly, if not all about sexy gals ... so the best way is to post only those that are nice but not sexy .... usually i post only close up of the head shots.
But why not look at the matter from another view ... if yr images are not good or nice, then why ppl want to leech them? So if you are not interested in financial gain, why bother at all? at least you keep seeing yr photos all over the place and you still have the original file ... that's a shiok feeling!