PNG
How the PNG image format works, when to use it for screenshots, and how it compares to JPG and WebP.
PNG (Portable Network Graphics) is a raster image format that stores pixels with lossless compression. Files use the .png extension and the image/png media type. The format is defined by a W3C specification and by ISO/IEC 15948.
PNG supports palette images with up to 256 colors, grayscale, and truecolor at 8 or 16 bits per channel, plus an optional alpha channel for transparency. Chunks inside the file can carry an embedded ICC color profile, gamma information and text metadata. macOS saves screenshots as PNG by default, and every current browser and image editor opens it.
Convert image formats
The Image Converter converts between PNG, JPG and WebP in the browser, and files stay on your device.
How PNG compression works
PNG first applies a prediction filter to each row of pixels, which records differences from neighboring pixels instead of raw values. It then compresses the filtered data with DEFLATE, the same algorithm used in ZIP files. Decoding reverses both steps exactly, so the pixels after decoding match the source. Large flat areas and repeated patterns compress well. Photos and gradients with noise compress poorly.
PNG vs JPG vs WebP
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| PNG | Lossless | Yes | UI, text, diagrams |
| JPG | Lossy | No | Photos, long frame sequences |
| WebP | Lossy or lossless | Yes | Web delivery |
When to use PNG
- Interface screenshots with small text and thin lines.
- Images that will go through OCR or a visual comparison.
- Graphics that need a transparent background.
- Master copies that will be edited and exported again.
Common mistakes
- Saving photos as PNG and getting files several times larger than needed.
- Converting a JPG to PNG and expecting the JPEG artifacts to disappear.
- Assuming PNG is always smaller than JPG for screenshots with photos or video frames.
Have an image to fix right now?
Shrink a large PNG with the Image Compressor or switch format with the Image Converter.
Common questions
Is PNG better than JPG for screenshots?
For interface screenshots, yes: PNG keeps text sharp. For photo-heavy frames, JPG gives smaller files at similar visible quality.
Does Temposhot export PNG?
Yes. The results pane offers PNG Export (Lossless), and Website Capture can save PNG instead of the default JPEG.
Sources
Related resources
- Export formats: PNG, JPG, PDF, MP4, GIF and WebP from a session.
- Image converter: PNG, JPG and WebP conversion.
- Image compressor: reduce file size in the browser.
Taking the same screenshots again and again?
Temposhot captures a screen, window or area on a timer and exports the set as a PDF, images, ZIP or MP4. The free browser tools fix single images.
Related resources
Related terms
- JPGHow JPG compression works, when to use it vs PNG and WebP, and common mistakes with lossy screenshot formats.
- WebPWhat WebP is, how it compares to PNG and JPG, and when to use it for screenshots.
- Lossless CompressionWhat lossless compression is, which image formats support it, and when pixel-perfect preservation matters.
- Image TransparencyWhat image transparency is, which formats support alpha channels, and how transparency works in screenshots and exports.
- Image CompressionWhat image compression is, lossy vs lossless explained, and common mistakes when compressing screenshots.
- Image FormatOverview of common image formats — PNG, JPG, WebP, AVIF — and when to use each.