Saving a layered edit straight to PNG or JPEG and closing the document, which discards every layer permanently.
Editing and retouching
Layer
Also called image layer, layers or layer stack. Here is what it means, when it changes what you export, and what people get wrong.
Editing and retouchingRuns on your deviceUpdated 10 August 2026
The short answer
A layer is one image stacked on top of others in an editing document, like a sheet of glass in a pile. Each layer has its own transparency, opacity setting and blend mode, and you can move, hide or restyle any one of them without disturbing the rest.
Updated
The short version
Layer at a glance
| Quick fact | Detail |
|---|---|
| Per-layer controls | Opacity, blend mode, visibility, mask |
| Layered formats | PSD, PSB, TIFF, XCF |
| Flat formats | JPEG, PNG, WebP, AVIF, GIF |
| Stack order | Upper layers cover lower ones |
| Merging them all | Called flattening |
Slide the table sideways to see every column.
What does a layer stack actually contain?
More than flat pictures. A working document usually mixes several kinds:
- Pixel layers: photographs, scans, painted areas.
- Adjustment layers: colour and tone changes that sit above the image and affect everything beneath without altering it.
- Text and shape layers: vector content that stays editable and crisp at any size.
- Groups: folders that let you move or hide a set of layers together.
Each layer carries an opacity value, a blend mode that controls how its pixels combine with what is below, a visibility toggle, and usually a mask. Order matters: upper layers cover lower ones unless a blend mode or transparency says otherwise. A layer with transparent regions simply lets the stack below show through, which is how compositing works at all.
Which file formats keep your layers?
Very few, and that surprises people at the point of export. Layers survive in editor-native formats: PSD and PSB for Photoshop, XCF for GIMP, and the equivalents in other applications. TIFF can also store a Photoshop layer stack, through private tags that only some software reads, so a TIFF opened elsewhere often shows just the flattened composite.
Every common delivery format is flat. JPEG, PNG, WebP, AVIF, GIF and BMP store one finished image. PNG, WebP and AVIF keep transparency, but not the separate layers that produced it. PDF and SVG have their own object structures and can hold separate elements, but they do not restore an editor's layer stack with its masks and blend modes.
The practical rule is to keep a layered master and export flat copies from it, rather than treating the exported file as your working version.
What people get wrong about layer
Each one is a real failure mode, not a style preference.
Assuming a TIFF keeps its layers everywhere, when the layer data sits in private tags that many applications ignore.
Working directly on the background layer instead of a duplicate, so the original pixels are gone once you save.
Questions people ask
Layer, answered
The follow-up questions people search for once they have the definition.
Can a PNG have layers?
No. PNG stores a single image, with an alpha channel for transparency but no separate layers, blend modes or masks. If you need those preserved, save a PSD or TIFF master and export the PNG as a copy.
What is the difference between a layer and a mask?
A layer holds image content. A mask is attached to a layer and controls which parts of that content are visible. One layer can have a mask, and hiding an area with the mask does not delete anything on the layer itself.
Do more layers make the file slower or larger?
Yes on both counts. Every pixel layer stores its own image data, so a document with dozens of full-size layers grows quickly and takes longer to redraw. Grouping, merging finished sections and using adjustment layers instead of duplicates all help.
What does layer opacity do that a mask does not?
Opacity fades the entire layer uniformly, in one setting. A mask varies visibility from place to place, so you can leave one area solid and another fully hidden. The two multiply together, which is worth remembering when an edit looks weaker than expected.
Same cluster
More from the glossary
Neighbouring entries, so every term in the set is one hop from every other.
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Sources
Where the facts on this page come from. Every link opens the specification, standard or documentation the claim was read at.
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