I'm pretty much "done" editting wikipedia (endless discussions about nothing, self-proclaimed vigilante endorsing self-written and badly formulated "rules" no matter if these fit the situation at hand, people pushing POV and getting their way etc. etc,), but I will still be contributing to Wikimedia Commons, so consider this to be my home base for wikimedia projects.
My contributions to commons will probably mostly be in the identification of arthropods and the occasional upload of images and related tinkering with categories etc.for taxonomy.
"Free" licenses such as the GFDL or Creative Commons licenses are mostly a "good thing" (R), but those licenses - well intended as they might be - also severely limit the remixer in ways that have huge impact on what can or cannot be done with the licensed work. It is my believe that the impact of the limitations is mostly unintentionally severe and often not at all what the author of the work had in mind, but the text of the licenses is quite clear imho.
For example: I like to create side-by-side images of "lookalike" species. Let's say I need to combine three species and have found three images that fit my purpose, all with free licenses. Now assume the licenses for the three to be something like CC-BY, CC-BY-SA and CC-BY-NC. All three licenses are intended to let me use the images for my purpose, a non-commercial, educational, collage or other remix (as long as I credit the original authors). But the differences in the chosen licenses make it legally impossible to combine the three. I cannot publish the resulting collage as NC as this would violate the SA. I cannot publish as SA, because this may violate the NC etc. etc.
Even the simple "BY" clause can make it harder to use the images in ways preferred by the remixer. It can make it cumbersome, distracting and downright ugly, breaking the page layout etc. to list some 10-20 author names on or near a bigger collage.
My images are (or at least used to be) mostly very mediocre, but may often show life forms or situations not generally found on other free images. I never intended to make money of my images, but create them for fun and maybe hope they may contribute to some bigger (educational?) purpose somehow, somewhere, sometime. Thus, I wish for non-commercial remixers that they may use my images with absolutely no limitation or clumsy requirements. Considering what is mentioned above, the only way to provide this, is a Public Domain dedication.
This means my images are also "up for grabs" for anyone less well intended, let's say to print them as post cards and sell them. Well, so be it. If you want to make money of my images and succeed, good for you. I was never even going to try and the total freedom for remixers that wish to use my images for education or similar purposes weighs in much more heavily - in my opinion that is. So all my own work will be Public Domain and/or CC0.
But note: Not all images uploaded by me are PD!. Sometimes I upload images that are not (entirely) my own work but are useful to have available on commons and carry a license that makes it possible to host these here. Needles to say, these will carry a corresponding non-PD license. Also, I may have created images with the help of others (such as access to natural history collections) that require some sort of attribution for that assistance. So these may also carry a non-PD license. So, be aware and always check the license on each image you want to use.
As I side effect of the PD/CC0 licensing, you also need not bother with requests for any usage. Just go ahead and use my images in any way you like. Don't waste my time (and your own) by getting permission. However, it is always nice to hear that my work has been put to good use, so feel free to drop me a note to the effect if so inclined. That will always be appreciated, so thanks!
Last but not least: My images are free. Free as can be. But running servers isn't(!) So, if you have a budget to spend on images for your project and if you feel that my images are worthwhile using, then please be a sport and donate some of your budget to the wikimedia projects - it may even be tax deductable.