Heh! I hear a lot of this about my lightning pictures. All of them are shot with only my Minolta 9 and standard color reversal or slide film. They may be cropped, and one or two might be color reversed for contrast. Otherwise the only Photoshopping that's done is maybe an unsharp mask, a color balance/white balance, or an auto level. That also speaks for all my other photos, too.
This particular photo is an optical illusion - the tree is in front of my house and the lightning strike is maybe 2 miles away.
This gives you an idea of how large the actual bolts can be:
