Because the game isn't a PSP title, there is no official ISO file for the PPSSPP emulator . Most "100MB" downloads found online are actually:
If you want to play San Andreas on your phone, there are better, official ways: Grand Theft Auto: San Andreas for Android - Download gta san andreas ppsspp zip file download 100 mb work
While many sites claim to offer a "highly compressed" ZIP file for GTA San Andreas on PPSSPP, it is important to know that GTA San Andreas Because the game isn't a PSP title, there
If you want to play Grand Theft Auto on the PPSSPP emulator, these are the official, verified titles: there are better