Raw or Enhanced Pictures

The answer for this one is subjective. Which do you think is best for placing photos on the website; raw and unedited picture or the edited and enhanced picture? Can the visitors determine if the picture has been edited or not?

What kind of photos do you mean? I think I don't understand the question. My answer would be different depending on if you're talking about stock photography to dress up a site, as opposed to say displaying a professional photographer's portfolio. For a professional photographer specializing in re-touching I think it can be helpful to show some before and after images.

Whether or not visitors can tell if a photo has been retouched would really depend on the skill of the photoshop user, in my opinion. There's a real art to making sure lighting and shadows look right in an "enhanced" photo.

Not sure what your question is, but you should not give out the original RAW file. You should be giving whom ever a finished version (edited/enhanced) and if they want Hi-Res make it something like a TIFF or Flattened PSD (if you dont want them seeing the edits)