Well first, don't use paint to to do any work to a photo you want to showcase your talent. It's not happening. There are NUMEROUS free photo-editing programs out there; Picasa and GIMP are just two.
Having said that, #1 is cool, but not necessarily digging the colors.
#2, needs light. Any light. It's a little flat, and its not doing the woman any justice.
#3 & #4 - re-resize those in another program. I'd dig the posing in #3 if I couldn't see the tarp underneath the two ladies. It feels posed, which isn't "bad" but it doesn't seem to make a tone here.
#5 has serious conversion issues.
So yea, first things first - lets get a real editing program going.