PSB
From Just Solve the File Format Problem
PSB (Photoshop's Large Document Format) is an image file format supported by Adobe Photoshop CS and later versions of Photoshop. It is a companion format to PSD. PSB supports larger image sizes (up to 300,000×300,000 pixels), and increases various other limits. PSB is nearly identical to PSD, except that some fields are larger.
Identification
PSB files begin with bytes '8' 'B' 'P' 'S' 0x00 0x02.
