The PSD format is the native file format of Adobe Photoshop.
The default extension is PSD.
Supporting Platforms and Applications
Adobe Photoshop and numerous applications on the Windows and MacIntosh platforms.
Supported bit counts are 1, 8, and 16. If the bit count is 1, the image is assumed to be monocrome (Color mode = 0).
0 No compression
1 MacIntosh PackBits encoding
2 Indexed color
3 RGB color
4 CMYK color
9 L*a*b* color