Hey there, Sethborill!
From your post, it sounds like you are experiencing an issue with unknown photos appearing on your iPhone Photos app. We're glad that you reached out to the Apple Support Communities. We want to try and help get you pointed in the right direction.
First, we see that you joined the Apple Support Communities from this article: Check your Apple ID device list to see where you're signed in. Did you see any unknown devices linked to your Apple ID? If so, did you have a chance to remove these devices?
Also, if you visit www.iCloud.com are these photos showing up there? Does anyone that you know have access to your Apple ID with your approval? If so, have you reached out to them to see if they took these photos?
Once more information is posted, others in the Apple Support Communities may be able to offer further assistance.
Take care!