What is a PSB file? A PSB file is a large image file saved in the Adobe Photoshop Big (PSB) format, which Adobe Photoshop uses to store high-resolution images that exceed the size limits of the standard Photoshop Document ( .PSD ) format. It contains all the same editable features as a PSD file, including layers, masks, text, and effects, but is used specifically for images larger than 30,000 by 30,000 pixels or greater than 2 GB in file size. PSB files are helpful for working on detailed or complex Photoshop projects that require more space than the PSD format allows.

More Information PSB file open in Adobe Photoshop 2025 Photoshop users save projects as PSB files when working with large graphics, such as detailed print layouts, 3D compositions, or high-resolution digital artwork, that require more space than the PSD format allows. The PSB format supports images up to 300,000 x 300,000 pixels, the maximum image size Photoshop permits. Adobe designed the format to maintain full editing capabilities on oversized projects without losing detail or structural data. Although PSB files are nearly identical to PSD files in terms of structure and functionality, they are not widely supported outside Adobe software. Most third-party image editors do not support PSB files, so using them in workflows that rely primarily on Adobe Photoshop is best.