Hello rsomp,
Thank you for reaching out to Apple Support Communities.
If it misidentifies him as a person, you can correct it and mark him as a pet using these steps:
"Fix misidentifications
- Open the Photos app on your iPhone.
- Tap Albums, tap People & Pets, then tap the person or pet that’s misidentified.
- Tap Select, then tap Show Faces.
- Tap the images that are misidentified, tap , then tap These are Not [name].
You can also fix misidentifications while viewing a photo in your library. Tap or swipe up to see the photo information. Tap the misidentified person or pet in the bottom-left corner of the photo, then tap This is Not [name]."
Additional details can be found here: Identify people and pets in Photos on iPhone
If the issue persists can you provide a few more details? Also, are you seeing duplicates of the same photos?
Cheers!