I have a legal question about copyright and I would very much appreciate your advice. I know Wikipedia is an open resource which can be used free of charge by the general public. Wikipedia has it's own collection of graphics. Is it legal to download graphics from Wikipedia and use it in a private or even commercial blog? Also, Which web graphics are completely free to use for commercial logos etc. without limitations of copyright laws?
To know if you may use the graphics on Wikipedia's site you will need to read their TOS. You may only use them if they say you may use them. The same goes for stock photo sites. Generally, you may use their stock photos on a personal site, but if you have a commercial site you need to pay them for a license to use the photo.
Many of the images used on Wikipedia are not in the public domain. Each image specifies the basis for its use on Wikipedia. Many of the images are licensed under various Creative Commons licenses. Typically, you are free to use CC-licensed images if you comply with the license requirements. For example, I have several images on Wikipedia or Wikimedia Commons under a CC license that requires that you attribute in the manner I have prescribed. If you use it without attribution, you are not complying with the terms of the license agreement and are therefore infringing my copyright. Other images are not licensed at all but are being used under a claim of fair use. Even though Wikipedia's use of an image may be fair use under the copyright laws, your use of the same image may not be. In short, you can not make ANY generalization about images on Wikipedia (or other sites such as Flickr). Different images are very likely to have different rules governing their use.
Many images are removed and replaced in Wikimedia on a regular basis, the reason being that the database is maintained by thousands of individual users. Often images are uploaded that have no business being there due to copyright; at least as often images are removed by self-styled do-gooders who don't actually know whether or not copyright is being violated or properly represented. Unless you have a lot of free time to spend digging through the individual permissions on a per-file basis, you're better off using something like Flickr's advanced search. http://www.flickr.com/search/?q=polar+bear&l=commderiv&ct=0&mt=all&adv=1 Code (markup): Copy that URL and change "polar+bear" to whatever your actual keyword is. That string is the Flickr advanced search that returns only photos that are usable for commercial sites, and can be modified, resold etc. Frank