TECTechnology
SVG vs PNG: Which Image Format Should You Use?
Published 4 min read
Use SVG for logos, icons, diagrams and illustrations made of shapes and flat colour, because it stays sharp at any size and is often tiny. Use PNG for screenshots, detailed graphics and images that need exact pixels with a transparent background. The difference comes down to vector versus raster: SVG stores instructions for drawing shapes, PNG stores a grid of coloured pixels.
Vector vs raster in one paragraph
A raster image is a mosaic of pixels, each with a colour. Enlarge it beyond its original size and the software has to invent pixels, so edges blur or turn blocky. A vector image is a set of instructions: draw a circle here, a curve there, fill this shape with blue. The device draws the image fresh at whatever size it is displayed, so there is nothing to blur. PNG, JPEG and WebP are raster formats; SVG is the main vector format on the web.
Side by side
| SVG | PNG | |
|---|---|---|
| Type | Vector (XML text describing shapes) | Raster (compressed grid of pixels) |
| Scaling | Sharp at any size | Sharp at its native size; blurs when enlarged |
| File size | Very small for simple artwork; grows with complexity | Grows with pixel dimensions and detail |
| Transparency | Yes | Yes, including soft edges |
| Photographs | Not suitable | Works, but files are large; JPEG or newer formats are usually better |
| Editing | In a vector editor or even a text editor | In a pixel editor |
| Styling and animation | Can be styled with CSS and animated | Static (APNG adds simple animation) |
| Compression | Text, can be compressed by the web server | Lossless |
When SVG is the better choice
- Logos and brand marks that appear everywhere from a favicon to a banner.
- Icons in an interface, where one file can be recoloured with CSS for hover states or dark mode.
- Charts, diagrams and maps that need crisp lines and readable labels on high-resolution screens.
- Simple illustrations with flat colours and clean shapes.
- Anything that will be printed at several sizes, since the same file serves them all.
Editing SVG no longer needs heavy desktop software. Our piece on the benefits of browser-based SVG editing software looks at tools that run in a tab and make sharing files with a team easier.
When PNG is the better choice
- Screenshots, where every pixel of text and interface needs to stay exact.
- Detailed artwork with textures, gradients and shading that would make an SVG enormous.
- Images with transparency that are not simple shapes, such as a product cut out from its background.
- Places that do not accept SVG, which still includes some email clients, social platforms and older content systems.
For photographs, neither is ideal. JPEG remains common, and newer formats compress far better at similar quality; our article on JPEG XL and image compression explains where that format stands.
Things that catch people out
Converting PNG to SVG does not add detail
Tracing tools can turn a raster image into vector shapes, and the result can be excellent for a simple logo. For a photograph, tracing produces either a crude poster effect or a huge, slow file. Wrapping a PNG inside an SVG file also changes nothing; it is still pixels.
SVG files can carry code
Because SVG is a text format that browsers interpret, a file can contain scripts and links. That is harmless in files you made yourself but a risk when a website accepts SVG uploads from strangers. Sites that allow uploads should sanitise SVG files or serve them in a way that prevents scripts from running.
Complex SVGs can be slow
An illustration with thousands of paths may be larger than the same image saved as PNG, and it takes processing power to draw. Simplify paths and remove hidden layers before exporting, or fall back to a raster version.
Accessibility works differently
A PNG relies on alt text. An inline SVG can include a title and description inside the file, and decorative ones should be hidden from screen readers. Either way, describe meaningful images for people who cannot see them.
A quick way to decide
- Is it a photograph? Use JPEG or a modern photo format.
- Is it made of shapes, lines and flat colour? Use SVG.
- Does it need exact pixels, rich texture or wide compatibility? Use PNG.
- Will it be shown at many different sizes? Lean towards SVG if the artwork allows.
Is SVG supported in every browser?
All current major browsers display SVG. Support in email clients and some third-party platforms is patchier, so keep a PNG version of logos for those places.
Does the format change how images appear in search results?
Search engines can index both. What matters more is that images load quickly, have descriptive file names and alt text, and suit the content around them.
Questions? Write to us.
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