[...]

I've got the disc image, but I don't know how to use the disc image to be able to play my game again...

[The J-man]

you need to burn the iso to a disc i use a program called power2go that came installed on my pc just choose what you want burn iso then put in blank disc find the iso and start it will go through then pop out the disc then it will ask you if you want to burn just put the same disc in and click okay then it will go through again then pop out the disc and say burn complete if done right you should just go put in the disc and it should work on playstation.