You need the raw game data. This can be done using a modified PS2 with a network adapter, or simply by using a PC DVD drive to rip the disc to an .ISO format.
Games originally sold by Sony on the PlayStation Store. Ps2 Pkg Games Download
The PS3 is the primary destination for PS2 PKGs. However, the situation is nuanced: You need the raw game data
PKGs use an encrypted save format, which is standard for the PS3 environment, though this can make moving saves to a PC emulator slightly more complex. Ps2 Pkg Games Download