PNG Image
ImagesA losslessly compressed raster image supporting alpha transparency, useful for logos and screenshots. Animation requires APNG-aware viewing software.
- What it is used for
- Transparent images, screenshots and diagrams
- What the file contains
- Binary data
All sections, questions and sources
Content reviewed： · Editor：Kai
First: choose for your purpose
PNG offers lossless compression and transparency. Separate compression, alpha and intended use when a logo turns white or a photo becomes large. Conversion to PNG does not recover quality absent from the source.
Opening steps
Choose your environment or purpose to see its steps.
Menu labels and support vary by app, OS and version. Preserve the original before making changes.
Troubleshooting by symptom
- Black/white transparent areas may be the viewer background or an alpha-incompatible output. Inspect alpha in an editor.
- A motionless image may be a static PNG or an APNG unsupported by the viewer.
- White background: distinguish actual white pixels from alpha rendering; JPEG conversion/pasting can discard transparency.
- Large file: inspect photo content, bit depth and dimensions; compression settings differ from discarding pixels.
- Animation stops: check APNG support versus a static-only viewer.
PNG → JPEG
- Open in an editor and composite transparent areas against the intended background.
- Export JPEG and inspect text edges and the background.
- Inspect alpha, background, edges, dimensions, color and any animation.
JPEG loses transparency and lossless storage. Retain PNG if small screenshot text becomes blurred.
Preserving transparency
Transparent PNG requires alpha in the image and its preservation during export; a white background layer remains white.
Inspect on light and dark backgrounds as well as checkerboard; halos and translucent shadows can become visible.
Source for these steps：GIMP Project · Export Image as PNG
Lossless compression versus conversion changes
PNG compression level itself is lossless, but reducing palette, bit depth or dimensions can remove information.
JPEG→PNG does not undo earlier loss; separate masters from web/submission copies.
Source for these steps：GIMP Project · Export Image as PNG
Related-format differences
| Format / choice | Purpose and preserved information |
|---|---|
| PNG | Lossless pixels/alpha; resizing/palette changes are separate operations. |
| JPEG | Photo format requiring alpha flattening. |
| SVG | Vector geometry rasterized when exported to PNG. |
Handling and security
Use an updated viewer and check the source; lossless compression is not a safety guarantee.
Questions and answers
Is every PNG transparent?
No. Some PNGs have no alpha transparency.
Can PNG animate?
APNG can carry animation, but the viewer must support it.
Does JPEG-to-PNG recover detail?
No. It can avoid further JPEG re-encoding, but cannot restore lost information.
Does PNG automatically remove backgrounds?
No; the image must actually contain transparency.
Does higher PNG compression blur the image?
PNG compression is lossless; investigate resizing/palette changes instead.
Format facts: name, steward and MIME type
- Formal name
- Portable Network Graphics
- Steward / specification
- W3C
- MIME type
- image/png
Primary and official sources
- StandardPortable Network Graphics, Third Edition
Defines lossless coding, transparency and animation.
W3C · Link checked： - Platform documentationConvert image file types using Preview on Mac
Documents Preview’s File → Export format selection.
Apple · Link checked： - Project documentationExport Image as PNG
PNG alpha, lossless compression and metadata.
GIMP Project · Link checked：