1. Download the gif from the link in the credits 2. Go to your profile page 3. Click your profile picture (it then either should say change or nothing and automatically ask for a file. Click change button) 4. Click on this gif and viola, you have a dog as your profile picture
https://mega.nz/#!HrQkSKCL (got gif from this video https://www.youtube.com/watch?v=YrKDxwLnxts) (credits to undertale for dog song)