Well I've used pics to make the textures for my landrover (
http://www.ofpec.com/yabbse/index.php?board=15;action=display;threadid=73 for pics) I just cut the pics down to the sections I want using Paint Shop Pro, then I resized them to the dimensions allowed by O2.
You've just got to use pics that are square on (front, back, sides, etc) for decent results, in my case I've used pics for the front, back and sides, and made the textures for the bonnet and roof since I couldn't get pictures of them. The two side textures are actually from the same picture (which I'll post tonight, once I get home from work, to give you an idea of what I mean), I just edited out the fuel filler cap for the left side (and a few blades of grass
)
Hope this helps
DLM