Hi Mad Boy I don't know if I can help but I save lots of photos, clip art and other images. I have folders for each type i.e. My Photos, My clip Art
My Smilies, My Backgrounds etc. When I see an image I want to save I do like you say and right click to Save Image or Save Target as, then find the appropriate folder and click save. I never really bother about file type. When I later need to insert an image I just go to Open or Insert find the saved image and insert. Sometimes I have to use the dropdown box to find the file type but never really have any problems.
With regard to your second question I'm afraid I don't know the answer.