Alright, everywhere I look I see image violations on AC. Even in the public gallery where images should ALL be okay, there's GOBS of violations.
I'm ill about this but I'll try not to go off on a tangent here. Here are the Image Submission Guidelines. READ THEM. FOLLOW THEM.
I realize that it's hard to understand some of it at first. You can't just slap any image on and that be that. Be aware that some of the approved AC image sources are not all free sources. Be happy that the submission guidelines are as detailed as they are now. They weren't that straightforward when I first started writing. I might not have had to go through the trial and error that I did had they been.
AC has, from time to time, jumped in and put pictures on or changed pictures on articles that they feel should be featured. They sometimes do not use pictures that we would recognize the credits on but rest assured, if AC is the one that placed an image on one of your articles, then the image is alright and you have nothing to worry about.
The Public Gallery
The AC public image gallery was supposed to be something to make placing images easier. But instead, it's a nightmare. Contributors who should know better are placing violating images on the public gallery and then unaware newbies are swiping them up. I've seen more instances of this then I can count. Please beware of the image gallery. For myself, I try to avoid it completely because I see more violations than not in there.
I'm upset at this because I dabble in hobby photography. I don't want anyone stealing my images just as much as I don't want someone stealing my articles.
Read a post I wrote back in January before I learned more about image submission. Maybe it will give you some ideas of alternative images you might use if you can't find what you are looking for.