What is the name of your state (only U.S. law)? CA...can I cut out pictures from old (1950) magazines paste them on white paper and sellthemm over and over on the web ?
Whether there is any legal risk in doing what you want to do will depend on the specific pictures and the magazines (among other things).
When you visit the site Zigner has provided the link to (
http://www.copyright.gov), you can look for information on "public domain" material.
If the pictures from the magazines are now in the public domain (published between 1923 and 1963 with the copyright not renewed; published before 1978 but lacking proper copyright notice and the notice was not restored; deliberately placed in public domain by owner; created by federal government)*, and if the magazine publisher does not hold copyrights in the material, it could be possible to cut the pictures out of the magazines and paste them on white paper and sell them. Material in the public domain can be used by anyone.
BUT, even if the pictures are clear of any copyright issues (and this is actually a pretty big "if"), there may be other rights that are still attached to the photos (ie, trademark rights, publicity rights). You need to ensure that the photos do not infringe on these rights.
To best avoid a lawsuit, I suggest you take the magazines you wish to cut up and sell, and have them reviewed by an attorney, prior to selling any material from the magazines.
*there are other ways works can be in the public domain, but what I listed could apply to copyrights in pictures from 1950 magazines