PNG vs SVG: When to Use Each Format (Complete Decision Guide)

The most common advice on PNG vs SVG is "use SVG for logos." That's correct but incomplete. The real reason is rooted in how each format stores image data — and understanding that unlocks when each format is the right tool and, critically, when SVG is the wrong choice (which most guides skip).

The Core Difference: Pixels vs Math

PNG is a raster format. It stores images as a grid of pixels, where each pixel has a specific color value. A 200×200px logo PNG contains exactly 40,000 colored squares arranged in a grid. If you display it at 400×400px, your browser doubles each pixel — blurriness is the result because there is no additional detail to reveal, just the original pixels stretched.

SVG is a vector format. It stores images as mathematical descriptions of shapes: "draw a circle at position (100, 100) with radius 50, fill it with #5b6af5." When you display it at any size — 16px or 1600px — the browser performs the math at that resolution. The result is always sharp, because the calculation is re-run at each size.

When to Use SVG

File Size: Why SVG Is Usually Smaller for Logos

A simple 3-color logo as SVG might be 2–5 KB. The same logo as PNG at 200×200px might be 20–80 KB. At retina (400×400px), that PNG balloons to 80–300 KB. The SVG stays at 2–5 KB regardless of display size.

This is why every major website uses SVG for logos and icons. A single SVG logo file serves perfectly on mobile (150px wide) and desktop (250px wide) without any srcset or media queries. One file, every resolution.

However, the file size advantage reverses completely for complex images. A photograph as SVG would require millions of tiny shape descriptions — the file would be larger than a JPEG by orders of magnitude, and the browser rendering would be extremely slow. SVGs are only efficient for geometrically simple graphics: shapes, lines, text, and limited flat colors.

SVG Performance Advantages on the Web

Beyond file size, SVG has a structural advantage: it can be inlined directly in HTML. An inlined SVG requires no HTTP request — the browser renders it as part of the HTML parse. For icons and logos, this eliminates a network round trip entirely.

Inlined SVG also enables CSS control: you can change an icon's fill color on hover without JavaScript:

.icon:hover path { fill: var(--accent); }

This is impossible with PNG — a PNG icon is a static image. Changing its color requires either a separate file, CSS filters (approximate), or Canvas manipulation.

When NOT to Use SVG (Common Mistakes)

SVG is not a universal upgrade. Avoid SVG when:

• The image is a photograph. Photos have too many colors to encode efficiently as vector shapes. Use JPEG or WebP.
• You need to display it in email. Outlook ignores SVG entirely (shows nothing). Always use PNG or JPEG for email images.
• The graphic has very complex artwork. A detailed illustration with thousands of colors and gradients may produce a large, slow-rendering SVG. Test the output file size.
• You're using auto-traced PNG-to-SVG conversion. Auto-trace tools (Inkscape's Trace Bitmap) often produce SVGs that are larger and more complex than the source PNG. Only use SVG when you have native vector source files.
• You need Open Graph / social sharing images. Twitter, Facebook, and LinkedIn do not support SVG as og:image. Use JPEG or PNG for social previews.

The Decision Framework

Ask two questions:

1. Was this image created in a vector tool? (Figma, Illustrator, Inkscape) — if yes, export as SVG.
2. Does this image contain photographic content? — if yes, use JPEG (photos without transparency) or PNG (screenshots, images needing transparency).

For anything in-between (icon libraries, UI components, brand assets), SVG wins almost always. The one exception is email — always test SVG in Outlook before deploying.

Frequently Asked Questions