How does this sound?
I have been putting this off for a few days to calm down. That did not work, haha. Having to deal with this again makes me so effing angry. If I were to call him, I would yell so much that I'd lose my voice. I swear to God, I will punch him in the face if I ever encounter him in public. I'm sending this to my ex-stalker boyfriend, who sent me a picture of my dog the other day like a creepy psychotic fuck. I am so sick of him harassing me. I want him to leave me alone.
If you still have pictures of my dogs and me after all these years, I want them returned to my mailbox immediately. Delete them now if they are on the computer you took from me. There is no reason you should have these pictures. Sending me a picture of my dog in the mail is completely unacceptable. Especially when this old picture of my dog was never sent to you in the first place; stop contacting me and making any attempts to communicate with me. I have moved on, and you have a girlfriend. I have no desire ever to reconcile what we once had. Your behavior is creepy AF, and I am done putting up with you harassing me.