You might be familiar with .pbp files (PSP Eboot). Popular tools like PSX2PSP convert PS1 games to PBP for the PSP and PS Vita.
To wrap up the long search for : The format does not natively work with the standard version of ePSXe without significant hassle. However, learning to convert your PS1 library to CHD is still a best practice for any serious retro collector. epsxe chd files
emulator does not natively support the (Compressed Hunks of Data) file format in its core configuration. While newer emulators like DuckStation You might be familiar with