how do i change my apple id photo on my ipad3

Your Apple ID photo should be the default photo when someone enters your number in their phone, unless "they" assign your contact a specific photo or someone shares a contact with a photo already on the contact file.

Welcome to the Apple Community.

Change it in your Address Book/Contact file.

By the way, the recipient of your text doesn't see the same picture as you.

What picture do they see?

The picture that "THEY" have of you in "their" contacts.