Downloading PS2 ISOs occupies a legal gray area. The generally accepted rule is that you should only download ROMs for games you physically own. That said, if you search for or "MK Shaolin Monks CHD" you will find various sources. Community forums like r/emulation on Reddit are excellent resources for help and guides.
Compressed disc-based games like this can sometimes impact loading performance because the emulator must decompress data "on the fly".