There are conditions placed on creative commons licensing. There is more than one type of CC license so it is important to find out which one applies. Some CC licensing prohibits being used commercially. Others not so but all require some form of attribution. By being on a Wiki the license type should be displayed as the Wiki page might have sourced them from elsewhere. The license however should be clear in the attribution. Using them in a commercial doco is not a simple assumption that they are public domain. You do need to check and attribute. Are you altering the image by cropping, flopping or coloring?
Sorry it’s not simple but the good thing is that if the Wiki pages has done its job the different type of CC license should be documented.