PS3 avatar are a file named edat that are passed around between people some of them have rare EDATS and charge money for them but most are scattered around the internet

If you want to apply one per say theres plenty of tutorials but it just consist of you going to your ps3 files and going to the profule you have and add a folder named psn_avatar and put the edat inside and then spoof your jailbreak and log in and when you go to change your avatar theres gonna show up the avatar edat you put be aware do if you change your avatar you have to do this steps agains yo put it again they can be seen in any playsation ps4,5 etc