: The current standard for disc-based emulation. It is lossless, meaning no game quality is lost, and it can reduce file sizes by CSO (Compressed ISO)
"Highly compressed" ISOs are created by stripping away this non-essential padding or by using advanced file formats: ps2 highly compressed games iso link
Options I can produce immediately:
Here are some popular PS2 emulators and ISO mounting software: : The current standard for disc-based emulation