I found a good article called “What Stock Photos Should Law Firm Web Sites Use?” that has helpful tips about using images, such as not using the most popular photos or ones that are cliche and literal, and not “going to the sites that appear on top of the search results.”
When you use images, you have to be very careful to make sure that you’re either paying for them, so that you’re not violating any copyrights, or you’re using free images that are royalty free. For instance, I don’t pay for the images that I put in my blog posts, but I make sure they are royalty free, in the public domain. I usually like to use clip art, but I wouldn’t recommend it for law firms because you want to make sure that all the images you use reflect the professionalism that you want to convey. I like to use clip art because it seems fun, but when people think of a law firm, I don’t think they’re looking for “fun”. Plus, some clip art just isn’t that good; if it isn’t chosen carefully, it can seem tacky.
If you don’t want to search for images online, you can take your own photos and post them wherever you want. That way, you can control the quality and be absolutely certain that you’re not violating any copyrights. In the end, it’s how you want others to see you: quality images that point to quality work.