I agree, pictures aren't as important to list for sources. It's highly unlikely that the owner of the sourced photos will stumble across their work on a random Steemit post. I do sometimes wonder what it would feel like to see someone make money from my images or songs. Giving credit to the artist may be the difference between a copyright lawsuit. Dramatic, but somewhat possible. Thanks for the comment
RE: 5 Reasons Why EVERYONE Should Name Sources On Steemit (Preventing Plagiarism And Mis-information).