§What is Commons current policy on GFDL and other licences inappropriate for images?
Commons strongly discourages this licence for new images:
Note: The GFDL is not practical for photos and short texts, especially for printed media, because it requires that they be published along with the full text of the license. Thus, it is preferable to publish the work with a dual license, adding to the GFDL a license that permits use of the photo or text easily; a Creative Commons license, for example. Also, do not use the GPL and LGPL licenses as the only license for your own works if it can be avoided, as they are not really suitable for anything but software.
Please note: The GFDL is rather impractical for images and short texts, because it requires the full text of the GFDL to be published along with the image. This is prohibitive for print media: in order to use a single image in a newspaper, a full page containing the GFDL would have to be printed. To resolve this, please dual-license your work under GFDL and an equivalent Creative Commons license like CC-by-sa-3.0 (see below). This helps to make your work usable not only freely, but also easily.
Wikimedia Commons also strongly disfavors content offered under licenses that impose impractical restrictions. For example, the GFDL technically requires that the complete license, a many-page document, be included with every copy of a work - even if the work is much smaller than the license! This type of restriction limits the scope of practical reuse. The Creative Commons licenses that Wikimedia Commons promotes help to balance the needs of content reusers, who want the attribution and license statement to be concise and practical, with the desires of the author, who often wish to be credited for their work.
§Why do people choose to give away their images with a free licence and no strings attached?
So that anyone can use them for any purpose at any time.
I get a buzz out of seeing my images in use. Who would have thought that I'd have a photo on a refrigerator magnet? That a local real estate agent would decide to use my images in a calendar? That the Boston Globe would use my images on its web site?
I find this kind of widespread usage of my photography far more rewarding the small financial gain I might have made by not releasing these photos under the Creative Commons license.
—William Warby, who has published 3,000 photos to Flickr under the Creative Commons License that have been used in everything from school textbooks to museum exhibits, iPhone apps and CD artwork.
Besides lots of reuses in accordance with the free license, I was contacted multiple times about paid commercial reuse without the CC-BY-SA terms (ad agencies, companies). I'm happy with either type of reuse and see no reason not to choose a simple free license.
We're a public institution, and so the art and objects we have are, in a way, everyone's property. With the Internet, it’s so difficult to control your copyright or use of images that we decided we'd rather people use a very good high-resolution image of the 'Milkmaid' from the Rijksmuseum rather than using a very bad reproduction.
§Why do people choose the GFDL as the sole licence for their images?
To restrict who can reuse the images or for what purpose. This is not compatible with the goals of Commons nor of Wikipedia (which is also a free content project).
For all my recent images, I use a GFDL-1.2 only license. In my opinion, this license allows me to restrict use of my images since it requires the user to include the license where the image is used. I usually waiver this requirement though if I get a request where the intended use is non-commercial. I do not mind my pictures being used by those who can not afford to buy them. What I despise is rich organizations who can afford to buy pictures being cheap and using them.
Nearly all [my images] are GFDL licensed and I use that to try to maintain a minuscule modicum of control over the images...For commercial uses sometimes I charge a small fee - put simply, if someone's making money off my images then I deserve some return...Simply there are some people I don't want using my images.
I'm contributing to increase the informative value of the articles on Wikipedia, not to contribute to a general free content movement....I dont want bloggers and newspapers randomly using my images. If they want to use my image they at least owe me the courtesy of asking - and usually I'll give permission for it to be used.
§Why shouldn't I prevent rich companies or evil people from using my images?
You can, but not with images uploaded to Commons. Other photo sites, such as Flickr, and stock and microstock sites will give you control over your images. This site only accepts free content that is available for anyone to use for any purpose without asking.
§What about people re-using a person's image for commercial gain?
This is a non-copyright restriction, covered by personality rights law. The people that are subjects of pictures on commons retain their right to control commercial use of their image. That is separate from the rights of the photographer or owner of the image. See COM:IDENT.
§Is this a decision for the Commons community or the WMF?
The community, with restrictions.
Historically the interpretation of which licenses are sufficiently free for Commons has been left up to the community, and that's where I believe it belongs. The WMF licensing policy specifies that licensing must be compliant with the Definition of Free Cultural Works, but whether specific licenses are or aren't consistent with the Definition for specific purposes is IMO a matter of such ambiguity that it requires ongoing community discussion. The GFDL and similar licenses that are being used for purposes other than the ones they were originally developed for are perfect examples of this dilemma, as they were clearly drafted to support free sharing of information, but nonetheless may not be appropriate in all circumstances.
§Wikipedia dual licences CC BY-SA 3.0 with GFDL. Is that still acceptable?
Yes. The CC BY-SA is an appropriate licence for images. Adding extra licence choices is permitted, even when those other licences aren't accepted on their own.
§Will this mean we delete all the images with just a GFDL licence?
Some of them are Featured Pictures. Many of them illustrate Wikipedia articles.
No. Existing media that has been inappropriately licensed will be retained. The owners of those works will be encouraged to add an appropriate licence.
§What licence should I pick that means anyone using my image in their article/journal/book must make it free too?
There aren't any such licences. Eric Möller suggested that a "CC BY-SA+" licence could be created with this power but this hasn't been created. Many, like Jimmy Wales consider this as overreaching what is reasonable, and to be impractical.
These terms are only well defined with regard to software licences such as GPL and LGPL. The definition of what constitutes a "derivative work" and what is "mere aggregation" is important. The former typically invokes the copyleft requirement whereas the latter does not. A weak copyleft licence may chose to not enforce copyleft for certain kinds of derivative works.
§What if I offer the image under different terms if reusers contact me?
Often people use the GFDL to let them vet who can reuse the image. But free images must not require the owner to be contacted and give ad hoc permission -- the licence should give permission to anyone for any purpose. Your account on Commons won't be around forever; you might change the email address; they may not have time to wait for your reply; they may not speak your language...
§Won't this change reduce the number of images Commons gets and drive off good contributors?
Not to any significant degree. Only a tiny minority of users uploading a small number of images still use this. The vast majority of images use a CC or FAL licence or are in the public domain. Images donated from organisations or transferred from other websites never use the GFDL -- it is a historical artefact of Wikipedia's early days and unused elsewhere for images.
We already disallow -NC images, which denies us access to a lot of otherwise-available images and puts off some contributors. The foundation of the site is free content for anyone.
§People just ignore the licence anyway so why the fuss?
If it is easy for people to behave honestly and legally, then they will. Straightforward licences like CC or FAL make it trivial for reusers to comply with the terms. Licences that are hard to understand, that appear to be inappropriate to the media or impose ridiculous burdens will tend to be treated with contempt and ignored.