Question: what is the difference between psb (photoshop big) and psd (photoshop document)?
Answer: PSB is a file extension for an image file used by Adobe Photoshop. ... The largest image size supported by a PSD file is 30,000 by 30,000 pixels. PSD file support has to be enabled in Photoshop's Preferences pane first, then PSB files can be saved at an image size up to 300,000 by 300,000 pixels.