A Little Help, Please?

Okay, I downloaded Picasa to my computer thinking I had to have it to put photos on my blog. Do I? I don't think I like it. :-( Can anyone help me out? If I understand correctly, it just organizes my photos right? If I delete Picasa from my computer, will I lose the photos that are on it? Does anyone else use it? Love it? Hate it? I can't figure out how to save an original photo and keep the edited photo both. Can I do that on Picasa? Any help will be greatly appreciated! Thanks!