Adding pictures to CS3??

Hey, I just got CS3 extended, and I'm not sure how to add pictures. Dragging works, but it only starts a new project with the picture as the background. Import Video Layer sometimes works, but it often says "Error: File is not part of a numeric sequence". Could someone tell me how to add pictures?

 

If you want to paste it onto another image also, like a render, you can paste special as new layer