Which Image Format to Use? The Complete Guide to Image Formats : JPG vs PNG vs WEBP

Illustration comparing JPG, PNG and WEBP image formats

Choosing the right file format can significantly impact your website's performance and user experience. Let's dive into three popular image formats - PNG, JPG, and WebP - and explore their characteristics, strengths, and ideal use cases.

PNG (Portable Network Graphics)

PNG was developed as an improved, non-patented replacement for GIF. This format uses lossless compression, meaning no data is lost when the image is compressed.

Key Characteristics:
  • Lossless compression
  • Supports transparency
  • Handles sharp edges and text well
  • Maintains exact color reproduction
  • Larger file sizes compared to JPG and WebP
Best Used For:
  • Images with text
  • Logos and icons
  • Screenshots
  • Images requiring transparency
  • Graphics with sharp edges and solid colors

JPG/JPEG (Joint Photographic Experts Group)

JPG is one of the most widely used image formats, known for its efficient compression of photographs and complex images with gradual color transitions.

Key Characteristics:
  • Lossy compression
  • No transparency support
  • Smaller file sizes than PNG
  • Some quality loss with each save
  • Excellent for photographs
  • Variable compression levels
Best Used For:
  • Digital photographs
  • Complex images with many colors
  • Web content where smaller file size is crucial
  • Social media sharing
  • Product photos

WEBP

WebP is Google's modern image format, designed specifically for the web, offering both lossless and lossy compression options.

Key Characteristics:
  • Superior compression compared to both PNG and JPG
  • Supports both lossy and lossless compression
  • Handles transparency
  • Supports animation
  • Excellent browser support (though some older browsers may need fallbacks)
Best Used For:

Size Comparison

To put things in perspective, here's how these formats typically compare in file size for the same image:

  • A photograph (2000x1500 pixels):
    • PNG: ~5.2 MB
    • JPG (high quality): ~1.8 MB
    • WebP (similar quality): ~1.2 MB
  • A logo with transparency (800x600 pixels):
    • PNG: ~200 KB
    • JPG (not recommended due to no transparency): ~80 KB
    • WebP: ~120 KB
Here is a comparison of a photo by Domenica Loia in three image formats.
A setup photo by Domenico Loia in jpg format
JPG - 293.63 KB
A setup photo by Domenico Loia in png format
PNG - 1.74 MB
A setup photo by Domenico Loia in webp format
WEBP - 115.74 KB

Original Size

293.63 KB

New Size

115.74 KB

60.6%

Size Saved

177.88 KB

Detailed stats of same JPG photo after being converted to WebP format.

Practical Recommendations

  • For Photography:
    • First choice: WebP with lossy compression
    • Second choice: JPG
    • Avoid: PNG (unless lossless quality is absolutely necessary)
  • For Graphics with Text and Sharp Edges:
    • First choice: WebP with lossless compression
    • Second choice: PNG
    • Avoid: JPG
  • For Web Development:
    • Use WebP with PNG/JPG fallbacks
    • Implement responsive images using multiple formats
    • Consider your target audience's browser support

Conclusion

While WebP offers the best of both worlds with superior compression and quality, it's still important to understand all three formats. PNG remains valuable for lossless quality needs, JPG continues to be widely supported for photographs, and WebP represents the future of web imagery. The key is choosing the right format based on your specific use case, considering factors like image type, quality requirements, file size constraints, and browser support needs.

Additional Resources

https://guides.lib.umich.edu/c.php?g=282942&p=1885348 https://developer.mozilla.org/en-US/docs/Web/Media/Formats/Image_types