general graphics question

Now I know before I even post this that something LIKE it has come up. The difference is that this goes a step beyond what's in the meories or what other people ask.

When ever I save a pic, it tries to save it as a bmp. I know, I get sick of seeing this question ever 3 days myself. The catch is that I've been having this problem for a few weeks now. I DO go to my internet tools and delete the cache, I've deleted cookies, I've done defragging, and that fun stuff that has gotten said in here before. And it works for a limited time, but after I leave the website that i'm on I need to go and clear out the cache again if I want to save pics as something besides bmp.

So just curious if there's a setting somewhere that I messed up and have no clue where it is, or if there's a troubleshoot that anyone can recommend to get rid of this once and for all, or if there's group counseling somewhere for other people that suffer from this same problem

Thanks again for any answers.