PSX games doesn't work as ISO, except if the image file is a raw image like IMG or BIN with .ISO as extension.
ISO normally are data images with sectors of 2048 bytes. PSX games normally use sectors of 2352 with data + audio tracks.
The start of each track in the image in defined in the CUE sheet or CCD. webMAN MOD can handle both file types. All other backup managers only handle CUE+BIN.
The cd image file should be a single file. Multi-bin images (like BIN + MP3 or BIN+WAV) are not supported.