What is PNG?
PNG (Portable Network Graphics) is a raster graphics file format that supports lossless data compression and transparency. It was created as an improved, non-patented replacement for GIF and is widely used for web graphics.
Quick Facts
| Full Name | Portable Network Graphics |
|---|---|
| Created | 1996 by PNG Development Group |
| Specification | Official Specification |
How It Works
PNG was developed in 1996 as a response to patent issues with the GIF format. It uses DEFLATE compression to reduce file size without losing image quality. PNG supports various color depths including 24-bit RGB and 32-bit RGBA (with alpha channel for transparency). Unlike JPEG, PNG is ideal for images with sharp edges, text, and graphics that require transparency. The format supports interlacing for progressive display and includes gamma correction for cross-platform color consistency. APNG (Animated PNG) extends PNG to support animation, offering better quality than GIF with full alpha transparency and 24-bit color. APNG is supported by all major browsers and provides a superior alternative to GIF for animated graphics, though file sizes are typically larger.
Key Characteristics
- Lossless compression - no quality degradation
- Supports alpha channel transparency (32-bit RGBA)
- Better for graphics, text, and sharp edges than JPEG
- Larger file size than JPEG for photographs
- Supports interlacing for progressive loading
- No animation support (unlike GIF)
Common Use Cases
- Website graphics with transparency
- Screenshots and screen captures
- Logos and icons with transparent backgrounds
- Graphics with text and sharp edges
- Images requiring lossless quality
Example
Loading code...Frequently Asked Questions
Why are PNG files larger than JPEG files?
PNG uses lossless compression, preserving every pixel exactly, while JPEG uses lossy compression that discards visual information. For photographs, this means PNG files are typically 5-10x larger than JPEG. However, for graphics with solid colors and sharp edges, PNG can sometimes achieve similar or even smaller sizes.
What is the difference between PNG-8 and PNG-24?
PNG-8 uses an indexed palette with up to 256 colors and 1-bit transparency (fully transparent or fully opaque). PNG-24 supports millions of colors (24-bit) and full 8-bit alpha channel transparency. Use PNG-8 for simple graphics and PNG-24 for complex images or when you need smooth transparency gradients.
Can PNG files have transparent backgrounds?
Yes, PNG supports full alpha channel transparency, allowing pixels to be partially or fully transparent. This makes PNG ideal for logos, icons, and graphics that need to overlay other content. PNG-24/32 supports 256 levels of transparency per pixel, enabling smooth edges and gradients.
Does PNG support animation like GIF?
Standard PNG does not support animation. However, APNG (Animated PNG) extends the format to support animation with better quality than GIF, including full alpha transparency and 24-bit color. APNG is supported by all major browsers but typically produces larger file sizes than GIF.
When should I use PNG instead of SVG?
Use PNG for raster graphics, screenshots, photographs with transparency needs, or when pixel-perfect reproduction is required. Use SVG for logos, icons, and illustrations that need to scale without quality loss. SVG files are often smaller for simple graphics and infinitely scalable, while PNG is better for complex photographic images.