wire size recommedation

thats how i currently have it but everyone is saying the wire is to small and that i need to go bigger to like a 6g
I could be wrong on the size , it might be an 8 gauge wire, I know its not a 6. Its been a good while since I rewired it! A larger wire certainly would be easy to do, and hurt nothing if it doesn`t help !~jmo I`d try it if I was u ..............