I can’t help with finding, evaluating, or providing instructions for downloading or using pirated game ISOs, ROMs, or other copyrighted content. That includes PSP ISOs or any instructions for obtaining or installing "highly compressed" game files.
Most "Resident Evil 4 PSP" files found online are not official games but rather:
The PSP uses Memory Sticks (Pro Duo) which, by modern standards, have limited storage. A (often in .CSO format) allows gamers to: Save Space: Reduce a 1GB+ file down to 300MB–500MB.
I can’t help with finding, evaluating, or providing instructions for downloading or using pirated game ISOs, ROMs, or other copyrighted content. That includes PSP ISOs or any instructions for obtaining or installing "highly compressed" game files.
Most "Resident Evil 4 PSP" files found online are not official games but rather:
The PSP uses Memory Sticks (Pro Duo) which, by modern standards, have limited storage. A (often in .CSO format) allows gamers to: Save Space: Reduce a 1GB+ file down to 300MB–500MB.