The online encyclopedia includes an image from 1315, said to be the earliest artistic portrayal of the prophet. The entry explains that most Muslims object to visual depictions, although the practice was better tolerated in medieval times.
About 100,000 people have signed a petition asking Wikipedia "to respect the religion" and taking aim at the images with the Muhammad entry. But many signatures support the images.
Wikimedia Foundation spokesman Jay Walsh said during an interview Thursday that the decision to "protect" edits from new and unregistered users -- and the decision to leave the images of Muhammad -- are made by editors and administrators. They make those decisions based on the values, principles, and policies of Wikipedia, which prides itself on not censoring people, he said.
"Noncensorship is an important tenet of the user community and the edit community," he said, adding that some images under anatomical entries can be considered offensive by some people.
Most pages can be edited by anyone, without requiring registration or prior experience. A section for Wikipedia's "frequently asked questions" explains various levels of protection assigned to pages where new user edits are blocked.
The site welcomes and encourages discussion among users and is always evolving, Walsh said. That means the protected status of the page could change.
"People have the ability to discuss whether or not an image should stay or go depending on the principles," he said.
Several pages of the online encyclopedia include depictions of the Muslim prophet.
An article on controversies surrounding depictions of Muhammad explains in detail several requests to remove art from public places. The final sentence of the article explains that the online petitions have requested removal from Wikipedia. The article also contains several images of Muhammad referred to within the text.
An entry explaining controversy over cartoons that portrayed Muhammad negatively shows those images.
The site's answers to frequently asked questions says Wikipedia does not censor itself for the benefit of any group.
The request for removal of the images has been aimed at versions of the online encyclopedia in several languages.
Wikimedia Deutschland explains that some Muslims oppose such depictions and feel offended by them. It points out that Shia aren't as strict as other groups on the issue. Mathias Schindler, who works for the German-language version, said "Wikipedia is an encyclopedia, not a venue for an inner-Muslim debate."
Walsh said that he doesn't recall the site drawing similar petitions from other groups, although there may have been similar requests regarding the Danish cartoons. There definitely was discussion of the topic and there continues to be discussion of the main Muhammad entry, he said.