So a few weeks ago I started doing a Children's Photographic Dicionary. I decided to get the bulk of the photos from Flickr, as Flickr lets you search by license. I've been searching Flickr for images specifically licensed as "Creative Commons-licensed content for commercial use, adaptation, modification or building upon". Maybe 99% of the images are from Flickr and the balance have been sourced from other websites that allow the use of their photos.
Because I have been searching in bulk I haven't been explicitly asking the owner of every single photo if I can use their photo for the dictionary. I've been assuming the commercial license and a simple link back for attribution is enough, since you have to go out of your way to specify that someone can use your image for commercial reasons - the default Flickr license is all rights reserved. I've been notifiying a subset of the photo owners, and others have noticed their photo is being used from the attribution link.
As a result, some people have asked their attribution link be changed somehow (you can contact me via this form), others have asked the link be direct to their home page rather than Flickr. Some photos were already explicitly tagged with various requests for a particular attribution, which I have respected. Most photographers have been very happy their photo has been used.
But one image that came up under the commercial derivitave search results didn't have such a happy ending. The owner retrospectively changed the license to "all rights reserved" and then put a takedown copyright violation notice to my host. I don't mind if someone doesn't want their image used - I'm happy to remove it and find another, particularly when it is just a photo of a common, everyday item like this one was, and there's no way I'd use a Flikr image that was marked as "all rights reserved" - they don't come up in my searches and Flickr blocks you from saving them to disk anyway.
At the time I found the photo the licensing was just fine, I'd given an attribution link back to the offending photo, and in theory I was in no violation of anything and could have used the photo. I've since been informed that the license that was in place at the time the photo was used is the one that counts, so legally the owner of this photo was on shaky ground changing the license before they issued the takedown notice but after I'd used it, and probably shouldn't have had their photo available for commercial use in the first place if other people using it was an issue - this has come up regarding Flickr images before. I consider the retrospective change of license and then contacting my host to be quite rude, and since that particular photo was nothing special it has long since been removed.
So if you're reading this when you're about to request some changes regarding a photo of yours I'm using (or a photo you are in and don't want the photo used), please try to be polite, and remember that I'm in Australia so if you send a message late at night in my time zone you're going to have to wait a few hours for a response, not a few minutes. I'm happy to change the attribution link in any way, or remove photos if requested, so you don't strictly need to bother the legal department of my webhost as a first point of call unless you don't get a reply within a day or so.
But of course if you're asking for the removal of a particularly unique photo that was very hard to find on Flickr (they exist - usually the more obscure concepts are quite difficult to find good photos for) I'm also quite open to negotiating a special license for those special photos!
And last but not least, for anyone wishing to use the photos on the photodictionary for derivitive works, it is best to follow the links back to the original images and check the original licensing - they were all originally released allowing derivitive work but not all were released as share-alike. And of course, the originals are higher resolution so it is worth going back to the originals just for that reason.