RenameIT

Image Format Deep Dive

Everything you need to know about choosing the right image format for quality, performance, and compatibility.

JPEG

Joint Photographic Experts Group

Best For:

Photographs, complex images with gradients, web graphics.

Pros:

  • Excellent for lossy compression, resulting in small file sizes.
  • Supports millions of colors (24-bit).
  • Universally supported by all browsers, devices, and software.

Cons:

  • Does not support transparency.
  • Lossy compression means quality degrades with each save.
  • Not ideal for images with sharp lines or text, as it can create artifacts.
PNG

Portable Network Graphics

Best For:

Logos, icons, illustrations, and images requiring transparency.

Pros:

  • Supports lossless compression, preserving all image detail.
  • Excellent for images with sharp lines, text, and flat colors.
  • Full support for alpha channel transparency.

Cons:

  • File sizes are significantly larger than JPEG for photographs.
  • Not ideal for very large images due to file size.
WebP

Web Picture Format

Best For:

A modern, versatile replacement for both JPEG and PNG on the web.

Pros:

  • Offers both lossy and lossless compression, often with better results than older formats.
  • Lossy WebP files are typically 25-34% smaller than comparable JPEGs.
  • Supports transparency and animation.
  • Excellent browser support in modern browsers.

Cons:

  • Not all older browsers or software support it natively.
  • Slightly more computationally intensive to encode/decode than JPEG.
AVIF

AV1 Image File Format

Best For:

Next-generation web images where maximum compression is critical.

Pros:

  • The most efficient format, offering the best compression-to-quality ratio.
  • Can achieve ~50% smaller file sizes than JPEG at similar quality.
  • Supports high bit depth, HDR, and transparency.

Cons:

  • Browser support is good but not yet as universal as WebP.
  • Encoding can be slow, making it better for static assets than dynamic generation.
GIF

Graphics Interchange Format

Best For:

Simple, short animations and graphics with very few colors.

Pros:

  • The standard for simple, looping animations on the web.
  • Supports basic transparency (1-bit, not alpha).
  • Lossless for its limited color palette.

Cons:

  • Limited to only 256 colors, making it unsuitable for photos.
  • Very inefficient file sizes for animations compared to modern video formats.
  • Replaced by PNG for static images and by video/CSS for complex animations.