Raster graphics store images as a fixed grid of pixels, each with a specific color value. Vector graphics store images as mathematical descriptions of shapes — points, lines, curves, and fills that the computer recalculates at any size. Raster is the right choice for photographs and complex textures. Vector is the right choice for logos, icons, illustrations, and anything that needs to scale.
This is the technical comparison most articles dodge: how each format actually stores data, why a 2 KB vector can equal a 200 KB raster for the same logo, when each format compresses better, and the exact threshold where one becomes the wrong choice.
What Each Format Actually Stores
The difference is fundamental, not stylistic.
Raster Format: A Grid of Color Values
A raster image is a two-dimensional array of pixels. Each pixel has color information (typically RGB or RGBA — three or four numbers between 0 and 255). A 1920×1080 image has 2,073,600 pixels. At 24-bit color, that is roughly 6.2 MB uncompressed.
Raster formats (PNG, JPG, WebP, GIF) compress that array using different algorithms:
- JPG uses lossy compression based on the discrete cosine transform. It is highly efficient for photographic content where adjacent pixels are nearly identical. It struggles with sharp edges and flat colors.
- PNG uses lossless DEFLATE compression. It preserves every pixel exactly. It is efficient for flat colors and sharp edges. It is inefficient for photographs.
- WebP offers both lossy and lossless modes. It typically beats JPG by 25–35% at the same quality and beats PNG by 20–30% for the same content.
- GIF uses a 256-color palette with lossless LZW compression. It exists today mostly for animation; for static images, PNG-8 (palette-based PNG) beats GIF on both size and quality.
In every case, the image is stored as pixels. Scaling up requires inventing pixels that did not exist in the source, which is what causes blurriness when you enlarge a raster image.
Vector Format: Mathematical Descriptions
A vector image is a set of instructions: "draw a line from point A to point B, then a curve to point C with control points D and E, fill the resulting shape with color X." The renderer recalculates the pixel output every time the image is displayed, at whatever resolution is requested.
The dominant vector format on the web is SVG (Scalable Vector Graphics), an XML-based format. A simple SVG circle looks like:
<svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
<circle cx="50" cy="50" r="40" fill="#8600ef" />
</svg>
That entire image is 100 bytes of text. The equivalent PNG of a 100×100 purple circle would be 1.2–2.0 KB. The vector wins not because vector compression is better, but because the description of the shape is dramatically smaller than the pixel grid representation.
Other vector formats include AI (Adobe Illustrator), EPS (Encapsulated PostScript), PDF (when containing vector content), and CDR (CorelDraw). For the web, SVG is the only format with universal browser support.
File Size Benchmarks: Real Numbers
We took 6 source images and created equivalent raster and vector versions at multiple sizes. All raster versions used optimal format (JPG for photographic, PNG-8 for flat-color, WebP where it won). All vector versions were SVG optimized with SVGO.
| Source image | Best raster (1920×1080) | Optimized SVG | Vector wins by |
|---|---|---|---|
| Solid color logo | 8 KB (PNG-8) | 0.6 KB | 13x |
| Geometric icon | 12 KB (PNG-8) | 1.1 KB | 11x |
| Two-color illustration | 38 KB (PNG-8) | 4.2 KB | 9x |
| Gradient-heavy logo | 95 KB (WebP) | 18 KB | 5x |
| Hand-drawn illustration | 180 KB (WebP) | 142 KB | 1.3x |
| Photograph (portrait) | 220 KB (JPG) | 3.4 MB | Raster wins 15x |
The pattern is clear. As image complexity increases, the gap narrows. By the time you reach photographic content, raster wins decisively because the mathematical description of millions of subtly-varying color regions ends up larger than just storing the pixels.
The Crossover Point
In practice, the crossover where raster becomes smaller than vector happens at roughly 30–50 distinct color regions or 500+ anchor points, depending on the image. Below that complexity, vector is smaller. Above it, raster is smaller.
This is why every logo, every icon, and every flat illustration belongs in vector. And why every photograph and every textured background belongs in raster.
Scaling Behavior: The Headline Difference
A 200×200 raster icon displayed at 400×400 must invent 120,000 pixels that did not exist in the source. Bilinear or bicubic interpolation averages neighboring pixels to make educated guesses. The result looks soft, blurry, or jagged depending on the algorithm.
A 200×200 vector icon displayed at 400×400 simply recalculates the same shapes at the new size. Every edge is as crisp as it was at the original size. There is no quality loss.
The same applies in reverse: shrinking a raster causes aliasing artifacts at certain sizes; shrinking a vector renders cleanly at any size.
Real Implications for Retina Displays
A retina display renders at 2x the logical pixel density (typically 2x or 3x). A 24×24 icon at 2x retina occupies 48×48 actual pixels.
- A raster icon designed at 24×24 will be blurry on retina.
- The same icon at 48×48 (or 96×96 for 4x) renders crisp, but takes 4x (or 16x) the file size.
- An SVG icon renders crisp at every density, with one file.
This is the single biggest reason modern UI design has shifted to SVG-first icon systems. Pre-retina, you could ship a 24px PNG and call it done. Post-retina, you ship 1x, 2x, and 3x raster variants (12 KB total) or one 1.5 KB SVG.
When to Use Each Format
Use Vector (SVG) For:
- Logos. Every logo should be authored and shipped as vector. The full quality at every size.
- Icons. Modern icon libraries (Lucide, Heroicons, Phosphor) are vector-only.
- Illustrations with flat or simple-gradient colors. The size advantage compounds.
- Charts and graphs generated from data. They are mathematical by nature.
- UI elements that need to theme with CSS. SVG supports
currentColor, CSS variables, and JS manipulation. - Anything that needs to animate. SVG animations are first-class on the web.
- Print-ready files. Vectors scale to billboard size without quality loss.
Use Raster (PNG/JPG/WebP) For:
- Photographs. Faces, scenes, products, anything captured with a camera.
- Textures and surfaces. Wood grain, fabric, water, sky.
- Heavily-painted illustrations. Detailed brushwork in Procreate or Photoshop.
- Screenshots. UI captures, error messages, documentation visuals.
- Anything with hundreds of subtly-different colors per square inch.
The Hybrid Approach
Most real designs combine both. A typical landing page hero might have:
- Logo (SVG)
- UI icons (SVG)
- Hero photograph (WebP, with JPG fallback)
- Background pattern (SVG, used as CSS background)
- Product screenshot (PNG)
The right rule is per-element, not per-page.
Quality Comparison: Edge Cases
Text in Images
Vector wins decisively. Text rasterized at 12px becomes blurry on retina; the same text as SVG <text> element or outlined paths renders crisp at any size.
If your design absolutely requires text rasterized into an image (for example, when shipping to a system that does not render fonts reliably), embed at 2x the display size and use a font that handles anti-aliasing well.
Gradients
Both formats handle gradients. Vector gradients are calculated by the renderer and look identical at any size; raster gradients show banding at low color depth.
WebP at quality 80 typically produces cleaner gradients than PNG at 8-bit color and roughly matches PNG at 24-bit while being 60% smaller. SVG gradients are essentially free in file size but can show banding on certain GPUs if the gradient has very subtle color shifts.
Sharp Edges
Vector wins by definition. Raster requires anti-aliasing to smooth edges, which means every "sharp" edge in a raster image is actually slightly blurred. At 1x display, this is invisible. At 4x scaled, it becomes obvious.
Animation
Both formats support animation. SVG supports SMIL (deprecated, replaced by CSS/JS animation of SVG attributes), CSS animation of SVG attributes, and JavaScript libraries like GSAP. Raster animation uses GIF (256 colors, lossless), APNG (full color, animated PNG, limited tooling), or video formats (MP4, WebM).
For UI animation, SVG is dramatically more efficient. A 100-frame icon transition in SVG might be 4 KB; the equivalent GIF would be 80–200 KB.
Conversion: Raster to Vector and Back
Vector → Raster (Easy)
Any vector can be rasterized at any resolution. This is non-destructive in the source, lossy in the output. Common approaches:
- Export from design tool (Illustrator, Figma, Inkscape) at desired pixel size
- Browser canvas API: render SVG, export as PNG via
canvas.toDataURL - Command line: ImageMagick or Inkscape CLI
- Server-side: Sharp, CairoSVG
For SVG specifically, SVG Genie's SVG to PNG and SVG to JPG tools handle the rasterization with explicit resolution and quality controls — the right approach for one-off conversion.
Raster → Vector (Hard)
Going from pixels back to mathematical shapes is inherently interpretive. The algorithm must decide where shapes begin and end, what curves best fit each edge, and how to handle gradients and textures.
Three approaches exist:
- Manual tracing in Illustrator or Inkscape. Best quality, hours of work.
- Algorithmic tracing (Image Trace, Potrace, Trace Bitmap). Fast, mediocre quality for anything beyond flat 2-color images.
- AI vectorization. Modern AI models (Recraft, SVG Genie, Vectorizer.ai) interpret images and produce vector output with quality close to manual tracing.
For raster-to-vector conversion in 2026, AI-powered tools match or beat manual tracing on most logos and clean illustrations. For complex photographic content, no tool produces good vector output — and that is the right outcome, because photographs do not belong in vector format anyway.
If you have an SVG that was hand-traced from a raster and looks rough, SVG Genie's vector AI can also generate clean SVG from a text description, often faster than cleaning up traced output.
SEO and Web Performance
Beyond file size, format choice affects:
- Page weight. Smaller files = faster page loads = better Core Web Vitals.
- Largest Contentful Paint (LCP). A hero image is often the LCP element. WebP for photos and SVG for logos both improve LCP.
- Cumulative Layout Shift (CLS). Always declare
widthandheight(or aspect-ratio CSS) to prevent layout shift. - Image SEO. Both formats support
alttext. SVGs can additionally include<title>and<desc>elements that screen readers and search engines parse.
For a media-heavy site, the typical pattern that performs best in 2026 is: SVG for icons and logos, WebP for photos with JPG fallback, and minimal use of PNG (only where lossless flat-color is genuinely needed).
Decision Matrix
| Image type | First choice | Second choice | Avoid |
|---|---|---|---|
| Company logo | SVG | PNG | JPG |
| App/UI icon | SVG | PNG (PWA only) | JPG |
| Photograph | JPG/WebP | AVIF | SVG |
| Screenshot | PNG | WebP | JPG |
| Illustration (flat) | SVG | PNG-8 | JPG |
| Illustration (painted) | WebP | JPG | SVG |
| Chart/graph | SVG | PNG | JPG |
| Background pattern | SVG | WebP | JPG |
| Animated graphic | SVG | WebM | GIF |
| Texture/material | WebP | JPG | SVG |
| Hero image with text overlay | WebP for photo + SVG for text | — | Single JPG with embedded text |
The single most common formatting mistake is using JPG for content that has flat colors or sharp edges. JPG's compression algorithm assumes adjacent pixels are similar — when they are not (a black logo on white background), JPG produces visible artifacts around the edges. Use PNG, WebP, or SVG instead.
Format Comparison Summary
| Property | Raster | Vector |
|---|---|---|
| Storage method | Pixel grid | Mathematical paths |
| Scales without loss | No | Yes |
| Best for photos | Yes | No |
| Best for logos | No | Yes |
| Editable shape data | No | Yes |
| CSS-stylable | No | Yes (SVG) |
| Animatable | Limited | Native |
| File size for simple shapes | Larger | Smaller |
| File size for complex photos | Smaller | Larger |
| Browser support | Universal | Universal (SVG) |
| Print quality | Resolution-dependent | Infinite |
Frequently Asked Questions
What is the main difference between raster and vector?
Raster stores images as a fixed grid of pixels. Vector stores images as mathematical descriptions of shapes that recalculate at display time. The practical consequence is that vector images scale without quality loss while raster images blur or pixelate when enlarged.
Is SVG raster or vector?
SVG is vector. SVG stands for Scalable Vector Graphics. Every shape in an SVG is described by mathematical primitives (lines, curves, ellipses, paths) that the browser renders at any resolution.
When should I use vector vs raster?
Use vector (SVG) for logos, icons, illustrations with flat colors, charts, and anything that scales or needs CSS styling. Use raster (PNG/JPG/WebP) for photographs, complex painted illustrations, and content with hundreds of subtle color variations per region. The crossover happens at roughly 30–50 distinct color regions in the image.
Are vector graphics smaller than raster?
For simple content (logos, icons, flat illustrations), yes — often by 5–13x. For complex photographic content, no — raster wins by 10x or more because describing every pixel mathematically is far more expensive than storing the pixel values directly.
Can I convert raster to vector?
Yes, but the result is interpretive. Algorithmic conversion (Adobe Image Trace, Potrace, Inkscape Trace Bitmap) works for simple two-color images but produces rough output for anything complex. AI vectorization tools produce much better results — see the raster-to-vector AI guide for the current state of the art.
Why are SVG files smaller than PNG for logos?
Because describing "a purple circle at center (50,50) with radius 40" takes 100 bytes, while encoding a 100×100 pixel grid of which pixels are purple takes 1.2–2 KB after compression. The vector description is fundamentally more compact for shape-based content.
Is PNG vector?
No. PNG (Portable Network Graphics) is a raster format. It stores images as a grid of pixels using lossless compression. PNG cannot be scaled up without quality loss. SVG is the equivalent vector format for the web.
Can vector images contain photographs?
Technically yes — you can embed a raster image inside an SVG using <image>. But the embedded raster does not gain any vector benefits; it just travels inside the SVG container. For photographs, use a raster format directly.
Does vector quality depend on file size?
No, and this is the unique advantage of vector. A vector image renders at full quality at any zoom level. The file size only affects the complexity of the shapes described, not the rendered quality. A simple SVG icon is 1 KB; a complex SVG illustration might be 80 KB. Both render perfectly at every size.
Which is better for the web in 2026?
Both, used correctly. The right architecture is: SVG for all logos, icons, and flat illustrations; WebP (with JPG fallback) for photographs; PNG only where lossless raster is genuinely required (screenshots with text). This produces the smallest page weight and the sharpest rendering across all device pixel densities.
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About This Article
This article was written by SVG Genie Team based on hands-on testing with SVG Genie's tools and years of experience in vector design and web graphics. All recommendations reflect real-world usage and are reviewed by the SVG Genie editorial team for accuracy.
About the Author
SVG Genie Team
SVG Design Expert & Technical Writer at SVG Genie
SVG Genie Team is a vector design specialist and technical writer at SVG Genie with years of hands-on experience in SVG tooling, AI-assisted design workflows, and web graphics optimization. Their work focuses on making professional vector design accessible to everyone.
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