It's legal under fair use, so don't worry about it.
http://libguides.mit.edu/usingimagesTake special note from the citation:
"Nature or type of work........Published, fact-based content."
More:
"What has been recognized as fair use?
Many types of uses have been found to be fair. Here's a small sample:
Criticism & Commentary
A book publisher used several stills from the famous 1963 Zapruder footage of President Kennedy's assassination for the historical book Six Seconds in Dallas. Time Inc., the owner of the footage, sued the book publisher for copyright infringement. In Time Inc. v. Bernard Geis Associates, the court ruled that the publisher's use of the stills was "fair and reasonable," in part because the use was based on a factual and historical news event.3
Parody
An episode of the TV cartoon "Family Guy" made fun of comedian Carol Burnett's image and signature characters from her 1960's comedy variety show. In Carol Burnett v. Twentieth Century Fox, the court ruled that the show's use was fair, in part because the "Family Guy" episode was designed to parody Burnett as a public figure, using a relatively small percentage of copyrighted material, and would not substitute for the original in any market.4
News reporting
The Washington Post newspaper used three brief quotations from Church of Scientology texts that were posted on the Internet. In Religious Technology Center v. Pagliarina, the court found the use to be fair, in part because the newspaper excerpted only a small portion of the work and the purpose was for news commentary.5
Art
American artist Jeff Koons used a portion of a designer photo advertisement (a model's legs in Gucci sandals) amongst a collection of iconic images in his painting, "Niagara." In Blanch v. Koons, the court held that the painting's use of the copyrighted images was a transformative fair use, in part because it commented on fashion and consumer culture.6
Scholarship and Research
A biographer of author Richard Wright quoted from six of Wright's unpublished letters and ten unpublished journal entries. In Wright v. Warner Books, Inc., the court found that the biographer's use was fair, in part because the biographer's purpose was to educate and inform the public, and his use constituted less than 1% of Wright's unpublished letters. 7
A researcher at a nonprofit foundation used quotations from an unpublished, historical literary work in her academic presentation. In Sundeman v. The Seajay Society, the court ruled that the researcher's use was fair and noted that the work was transformative and was used solely for the purpose of scholarly analysis. 8
Time-shifting
A major electronics manufacturer developed a video tape recording device that allowed the consumer to "time-shift"—record a complete TV program in real-time and hold the show for a later viewing. Several major film studios filed a copyright infringement suit against the electronics manufacturer claiming the device could be used for copyright infringement. In 1984's Sony v. Universal Studios (aka the Betamax case), the Supreme Court held that time-shifting with a VCR qualified as fair use. The courts noted that the private, non-commercial home taping of free television programs for later viewing was not infringing and did not hurt the market value of the copyrighted material.9
Search Engines
A Google search engine turned the photos on a subscription-only website into thumbnail images for its search results. In Perfect 10 v. Amazon.com et al, the court ruled that Google's use of thumbnail photos was "highly transformative," since the search engine changed the image's original purpose of entertainment and aesthetics into providing Google's users with links to images."
http://www.teachingcopyright.org/handout/fair-use-faqUse his published images, have a good time and let him whine!
My $.02.
