this function is prepared to read the photoshop files (.psd) in Mode RGB 8 bits/channel and grayscale.
available:
layered image data
RGB with 2 alpha channels
RGB with 1 Alpha channel
RGB sans alpha
Grayscale with 2 alpha channels
Grayscale with 1 alpha channel
Grayscale only
developing:
Indexed with 1 alpha
Indexed only
nonlayered image data
available:
layered image data
RGB with 2 alpha channels
RGB with 1 Alpha channel
RGB sans alpha
Grayscale with 2 alpha channels
Grayscale with 1 alpha channel
Grayscale only
developing:
Indexed with 1 alpha
Indexed only
nonlayered image data