I honestly forgot I made this mod a couple of years ago, took me a while to make and edit, I remember I couldn't find a Tupac tattoo mod high res, you can also use the original tattoos on CJ at the tattoo parlour but the 2pac tattoos are pre-applied you cannot remove them, there is also high res clothes and jewellery included, and a personal touch to one of the tattoos. 

back up your player.img folder located in modloader folder, replace the player.img folder with the one downloaded from here, done!
if you haven't got a player.img folder in your modloader just place the downloaded one in there. 

be aware this mod also smooths Cjs skin tone, and makes him look cleaner, including his face higher res, if your cj is pure muscle or fat this mod will not work, he needs to be skinny/slim like Tupac's build in real life. you can make cj bald at the barber shop or have whatever style hair you prefer.

Please let me know if this works for you on your end as I haven't played GTA sa for years now and just thought I'd share this in case there's someone out there like me all those years ago who wanted some Tupac tattoos on their body

Enjoy!