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Open a PSB file online

PSB is the large document format that Photoshop uses once a file passes 2 GB or 30,000 pixels on a side. Photostar reads PSB files in your browser with their layers, so you can check what is inside without the program that made it.

Photostar is a free online Photoshop alternative that runs in your browser. There is no account to make, and your files stay on your device.

Open a PSB fileOpens the free editor. Nothing is uploaded.

How to do it

  1. Open the PSB. Click the button above, or open Photostar and drop the .psb file onto the start screen. It is read on your computer.
  2. Wait for the layers. A big PSB takes a moment. When it is ready, the Layers panel lists each layer and group from the file.
  3. Look around. Hide and show layers with the eye icons. Hold the space bar and drag to move, and press Ctrl or Cmd with plus or minus to zoom.
  4. Save what you need. Choose File → Export As for a flat PNG or JPEG of the visible layers, or File → Save as PSD to keep the layers.
A layered PSB file open in Photostar, with Circle and Background layers listed in the Layers panel
Screenshot: A two-layer PSB open in the editor. Both layers came through with their names. Captured 12 November 2026.

What is supported

What works

  • Pixel layers, groups, masks and supported text and shape layers, as with PSD files
  • Viewing, editing and exporting PNG, JPEG, WebP, TIFF and more
  • Saving the layered result as a PSD

Limits

  • Photostar does not save PSB. A PSD holds up to 30,000 pixels per side, so crop or resize a bigger document before saving it layered
  • The whole file has to fit in your browser’s memory. Files of several gigabytes may fail on a laptop or phone
  • Complex layer features can look different from the original; check the result before sending it on

Questions

What is a PSB file?

A PSB is a Photoshop Large Document. It works like a PSD but allows bigger files, up to 300,000 pixels on a side, so it is common for posters, panoramas and print work.

Can I open a PSB file without Photoshop?

Yes. Photostar opens PSB files in a web browser for free, with their layers, and nothing is uploaded.

Can I convert a PSB to PSD?

Yes, if the image is no wider or taller than 30,000 pixels. Open the PSB and choose File → Save as PSD. For a bigger image, resize it first with Image → Image Size.

Why does my PSB fail to open?

Usually because it is too big for the memory a browser tab can use. Try a computer with more memory, or ask for a flattened PNG or a smaller PSD.

Related

Reviewed , with a real file of this kind in the current editor.

Open a PSB file