How do I hang pictures without nails?

Have you tried the Command products that's what I use on my walls

I know Command strips work for many of my things. I've not tried the ones intended for heavy art. Removing them works just like they say, no residue and no marks.

I use Command Hooks, but they will leave a mark if left like a year. Another old fashioned alternative is to use needles. They will hold 10 lbs of weight and you cannot see their hole if you move the needle. Hope this helps.

Ok, it was nice to see all the fast responses...I will try your suggestions and see what works best for me. Thank you so much!

If you use the command strips, they show weight limits on them. I always purchase the ones that are somewhat above the weight of what I am hanging. Use a minimum of four on pictures, if it is really heavy picture, I would use two on each of the four sides. I hung the speakers for our surround system using the strips and as small and heavy as the little speakers are, they hold with two strips on each without a problem. Two of them have been in the same place for three years now and never have fallen. Make sure you follow the directions for leaving them to sit before you hang anything on them and make sure that where you are putting the strips is really clean and dry.