While waiting to get file, you can do this, and this step is for those who would like to personalize their stuff like me.FYI, CEX is PS3 version for consumers and DEX is for developers, change if you know what it is.
Then click Decrypt, and it will take a while depending on the file size. Select your PS2 ISO game as Encrypted Image if it pops up to ask you to Add LIMG Sector, just choose Yes. Now, run PS2Classics_GUI.exe, by default, you are at Encrypt tab.DO NOT leave any empty space in ISO’s file name.To make PS2 games pkg, it has 2 steps, they are decompressing from PS2 ISO and packaging into a pgk file.In short, that folder is a working folder of that file, so I would recommend you to have desktop shortcuts for both. Locate PS2Classics_GUI.exe file and PS2U10000 folder inside the directory where you installed PS3tools (folder ‘tools’).I assume you already download your PS2 games, and in my case, the games are always in ISO.