A senior researcher, with whom I worked a few years ago, is writing a book chapter. He contacted me to ask what was the latest work of our group on the topic of his chapter. I gave him a few links to recent articles and the preprint of an article soon to be published. He followed up by asking if “[you] would have a figure to illustrate [topic of the preprint]… preferably something that does not require copyright authorization paperwork”.
At first, I thought that was a bit much to ask… I had never asked for figures from anybody who was not an author on the paper. But the situation may be different for a book chapter, and obviously I'm glad to share the news of our most recent results. So, I took an hour tonight to make a nice illustrative figure, and am about to send it. However, I'd like to make certain in my mail that I ask for some sort of acknowledgment. So, my question is: if someone designed a figure for a book chapter, how would that person be acknowledged? in the figure caption, e.g. “figure courtesy of X”? in another way?