Vector vs Raster Graphics
Every digital image belongs to one of two families: raster or vector. The difference decides how large the file is, how far it can be enlarged, which software can edit it, and what happens when you convert it. This guide explains how each family works, what rasterizing means, and when each type is the right choice.
What Is a Raster Image?
A raster image is a grid of pixels — a fixed number of small squares, each holding a single color. A photograph taken by a phone camera is raster: the sensor captures millions of pixels, and the file simply records their colors. Common raster formats include PNG, JPG, WebP, GIF and BMP. Nearly everything you see on a screen is raster at the moment it is displayed, because screens themselves are pixel grids.
The defining property of a raster image is that it is resolution-bound: the pixel grid is fixed when the file is created, so the image has exactly one native size. Display it smaller and it still looks fine; display it larger and the software has to invent pixels that were never captured, which shows up as blur or blockiness. Shrinking is safe; enlarging is where quality is lost.
What Is a Vector Graphic?
A vector graphic stores drawings as descriptions rather than pixels: a line from here to there with this thickness, a curve through these points filled with that color, text set in this font at that size. The software that displays it computes the pixels on the fly, at whatever size is needed. SVG on the web and Adobe Illustrator’s .ai format are the vector formats most people encounter; PDF is a mixed format that can contain both vector and raster content.
This makes vectors resolution-independent. The same SVG file is perfectly sharp as a 16-pixel favicon and as a billboard-sized print, because there are no pixels in the file to run out of. Vectors suit flat, geometric artwork — logos, icons, diagrams, typography, illustrations built from shapes. They are a poor fit for photographs, whose continuous tones and fine detail would require enormous numbers of shapes to describe. That job belongs to raster.
Key Differences at a Glance
| Aspect | Raster | Vector |
|---|---|---|
| Scaling | Fixed pixel grid; enlarging beyond native size loses sharpness | Scales to any size with no loss of quality |
| Transparency | Supported by PNG and WebP; JPG has none | Inherent — areas not covered by shapes are simply empty |
| File size | Grows with pixel dimensions; photos can be large | Small for simple shapes; grows with drawing complexity |
| Editing | Pixel editors retouch colors and areas; lossy formats degrade on repeated saves | Paths, colors and text stay individually editable at any time |
| Typical formats | PNG, JPG, WebP, GIF, BMP | SVG, AI, EPS; PDF (mixed content) |
| Best uses | Photographs, screenshots, detailed textures | Logos, icons, diagrams, print artwork, illustrations |
What Rasterizing Means
Rasterizing is the act of converting vector geometry into a fixed pixel grid. When an SVG is displayed in a browser or an Illustrator file is exported as a PNG, the drawing instructions are executed at a specific size and the result is baked into pixels. It is a one-way trip: once rasterized, the path data is gone, and enlarging the raster later cannot recover the crispness the original vector had.
That is why the output size deserves a deliberate choice at conversion time. Render a logo SVG at 200 pixels wide and it will look fine as a thumbnail but soft on a large screen; render it generously and you can always downscale later with no loss. When you rasterize an SVG in our converter, the downscale option lets you pick the output dimensions — for example 100, 75, 50 or 25 percent of the rendered size — so the raster you get matches where it will actually be used. Upscaling is intentionally not offered, because inventing pixels adds nothing but blur.
When to Use Each
For logos and icons, the working rule is: keep a vector master, ship raster exports. Designers keep the SVG or .ai file as the source of truth and export PNG (or WebP) copies at the specific sizes a website, app or document needs, so every placement is sharp and a new size is one export away.
For photographs, raster is not just the best choice — it is effectively the only choice. Cameras and scanners capture pixels, and the continuous tone of a photo is exactly what lossy raster formats like JPG and WebP were designed to compress efficiently. Converting a photo to vector would either fail or produce a stylized tracing rather than a faithful copy. Choosing between the raster formats themselves is its own topic, covered in PNG vs JPG vs WebP: Which Image Format Should You Use?
Common Questions
Can I convert a PNG to vector?
Not by renaming the file or using a format converter — a PNG contains pixels, and no tool can recover path data that was never there. Automatic tracing software can redraw a raster image as vector shapes, with results that vary widely: clean, flat logos trace well, while photos and soft gradients do not. That kind of tracing is outside the scope of our converter, which converts between raster formats and rasterizes genuine SVG files.
Why does my logo look blurry?
Almost always because a raster version of it is being displayed larger than its pixel grid allows — for example, a 250-pixel-wide PNG stretched into a 500-pixel space. The pixels cannot be regained after the fact. Ask the designer for a larger export or, better, an SVG version, which will stay sharp at every size the site or document needs.
The short version: vectors are masters, rasters are deliveries. Keep the editable vector where you can, and rasterize deliberately. When you need a fast, private conversion — SVG to PNG, PNG to WebP, and more — the AI Image Converter runs entirely in your browser.