The is designed to run Sony PSP games. Since Rockstar Games never ported San Andreas to the PSP, there is no official ISO file for it.
Below is a comprehensive guide on what these files actually are, how they work, and the reality of "highly compressed" gaming. gta san andreas android highly compressed 50mb ppsspp
While it is a popular search topic, it is important to clarify a major technical distinction: The is designed to run Sony PSP games