.png MIME type
PNG imageimages
image/pngLossless raster images with transparency.
| MIME type | image/png |
|---|---|
| Extensions | .png |
| Content-Type | image/png |
| Compress in transit? | No — already compressed |
| File signature | 89 50 4E 47 0D 0A 1A 0A (.PNG....) |
Good to know
- Already compressed — gzip or Brotli gain almost nothing, so servers shouldn't compress PNGs.
- For photos, WebP or AVIF are usually much smaller; keep PNG for screenshots, UI and images that need exact pixels.
Serve .png files with the right type
The response header to send:
Content-Type: image/png
Most servers pick the type from the file extension. If yours sends the wrong one, map it explicitly:
nginx (inside the types block in mime.types)
image/png png;
Apache (.htaccess or server config)
AddType image/png .png
Express
res.set("Content-Type", "image/png");Python
import mimetypes
mimetypes.add_type("image/png", ".png")HTML file input
<input type="file" accept=".png,image/png">
Check it
See what a server sends for a file, and what type a local file really is by its contents:
curl -sI https://example.com/file.png | grep -i '^content-type:' file --mime-type file.png
Frequently asked questions
What is the MIME type for .png files?
image/png.
What Content-Type header should a .png file be served with?
Content-Type: image/png. It's already compressed, so servers shouldn't gzip it.
How can I tell if a file is really a .png?
Check its bytes rather than the extension: PNG files start with 89 50 4E 47 0D 0A 1A 0A (.PNG....). On the command line, file --mime-type name.png does this for you.
Related types
Headers that go with it: Content-Type · Content-Disposition · X-Content-Type-Options