SVG vs Raster Images: Which Format to Use for Logos, Icons, and Photography

A decision guide for picking between vector (SVG) and raster (JPEG/PNG/WebP/AVIF) image formats, with file-size comparisons and retina-display considerations.

At a Glance

SVG (Scalable Vector Graphics) stores mathematical drawing instructions and scales infinitely without quality loss: use it for logos, icons, illustrations, and charts. Raster formats (JPEG, PNG, WebP, AVIF) store per-pixel colour data: use them for photography and complex colour gradients. A typical icon is ~500 bytes as SVG vs ~15 KB as PNG (30× smaller). On retina displays, SVG stays crisp at any scale while PNGs blur once stretched beyond their native dimensions. Best practice: SVG for all UI chrome, WebP/AVIF for photography, PNG-8 only for ≤256-colour graphics requiring wide compatibility.

What Is the Fundamental Difference Between SVG and Raster?

Raster images store a colour value for every pixel in a fixed grid: a 1000×1000 px PNG contains one million colour values. SVG stores the mathematical instructions to draw shapes (paths, circles, rectangles, gradients) and the browser redraws them at whatever size is requested. That single architectural difference drives every other SVG-vs-raster trade-off. The <a href="https://developer.mozilla.org/en-US/docs/Web/SVG" target="_blank" rel="noopener noreferrer">MDN SVG reference</a> documents the full specification.

  • <strong>Raster</strong>: fixed pixel grid; resolution-dependent; degrades when scaled up
  • <strong>SVG</strong>: XML-based vector instructions; resolution-independent; scales without quality loss
  • <strong>Raster file size</strong> grows quadratically with resolution (2× wide = 4× bigger)
  • <strong>SVG file size</strong> depends on shape complexity, not output dimensions
  • <strong>SVG is text</strong>: human-readable, editable in code, animatable with CSS

When Should You Use SVG?

Use SVG whenever an image is built from geometric shapes rather than photographic detail: logos, icons, illustrations, data visualisations, decorative graphics. SVG file sizes are often dramatically smaller than equivalent PNGs: a simple icon that would be 15 KB as PNG can be 500 bytes as SVG. SVG also scales perfectly on retina and ultra-high-DPI displays, animates with CSS or JavaScript, and accepts runtime styling (colour changes via <code>fill</code>).

  • <strong>Logos</strong>: must scale across favicons, headers, social previews
  • <strong>Icons</strong>: UI chrome that needs to render crisply at every DPI
  • <strong>Illustrations and diagrams</strong>: geometric content that benefits from infinite scaling
  • <strong>Data visualisation</strong>: SVG charts are interactive and accessible by default
  • <strong>Decorative graphics</strong>: background shapes, dividers, pattern overlays

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