I'm thinking of forcefully putting up pictures of my own dog in MIL's house
Why does she need to have pictures of your dog?
I think my dogs are being ignored and I'm sick of it.
You need to respect your MIL's house and not put pictures of your dogs up. Your MIL can decorate the house as she wants and you can't choose what should be up there.
Fuck you. I'm sick of everyone treating me this way like I'm a child.
The way you are acting is going to get you treated that way. If you mother in law does not want to have pictures of your dogs, you should not force the issue. You need to have more respect for her property.