: Photoshop Reducing File Size by Hiding Layers I've recently learned that hiding Photoshop layers will reduce the file size. After searching around the Adobe forums I can't find anything stating

@Nimeshi706

I suspect it would take someone from the Photoshop Dev team to really explain this clearly.

My understanding is that internal proprietary data regarding visible layers is either included or not based on layer visibility state. This is combined with the internal composite preview to further alter file size.

For example, if a layer is not visible, Photoshop does not need to store the data generated when the layer is visible. Things like anti-aliasing, blend modes, opacity variations, etc. (essentially blending options) are all superfluous when a layer is not visible. So that data does not need to be stored and can quickly be regenerated when the layer is made visible at a later point. Blending options data can get lengthy because each layer can interact with every layer below or above itself.

The short answer... Composite data is stored differently.

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@Rambettina927

A file preview is not the same as a flattened, full res snapshot of your image. The latter is saved for compatibility purposes, when you save it as such. The layers are flattened but there should be no other form of compression in the compatibility version of the file, hence the large size.

If you don't need to worry about compatibility, which you obviously don't if you're turning the layers off, then just turn off compatibility mode. It's usually inactive on my files. If you have to distribute a file for another person's use, just save a version.

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@Phylliss782

I just did the test and in fact in my test with all layers hidden got a file about 1 MB smaller.

I proceeded to save it with all layers visibility on but this time disabling the "maximize compatibility" option - the result was the same.

So the thing is, Photoshop saves some kind of high res preview of the file when "maximize compatibility" option is turned on. This info is then used in programs like irfanView, google viewer and even adobe bridge for previewing purposes. With all layers visibility hidden this preview will be essentially empty thus the file size decrease.

You can turn off maximize compatibility in preferences > file handling

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