Image
Portable Network Graphics is a image format commonly identified by .png. Use the listed signatures, MIME types, and structure notes to validate files beyond the extension.
89 50 4E 47 0D 0A 1A 0A .PNG....SIGNATURE = bytes.fromhex("89504e470d0a1a0a")
OFFSET = 0
def is_png(path: str) -> bool:
with open(path, "rb") as f:
f.seek(OFFSET)
head = f.read(len(SIGNATURE))
return head == SIGNATUREconst SIGNATURE = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
const OFFSET = 0;
// bytes: a Uint8Array / Buffer holding the start of the file
export function isPng(bytes) {
return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}package fileid
import "bytes"
var ispngSignature = []byte{0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a}
const ispngOffset = 0
func IsPng(b []byte) bool {
end := ispngOffset + len(ispngSignature)
if len(b) < end {
return false
}
return bytes.Equal(b[ispngOffset:end], ispngSignature)
}const SIGNATURE: &[u8] = &[0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
const OFFSET: usize = 0;
fn is_png(bytes: &[u8]) -> bool {
bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}<?php
$signature = "\x89\x50\x4e\x47\x0d\x0a\x1a\x0a";
$offset = 0;
function is_png(string $bytes): bool {
global $signature, $offset;
return substr($bytes, $offset, strlen($signature)) === $signature;
}Portable Network Graphics is commonly used for image previews, thumbnails, metadata checks, and upload validation. Test multiple sizes because resolution, alpha support, compression, and file size often affect implementation behavior.
Media files can still stress decoders through corrupt metadata, extreme dimensions, long durations, or unusual chunks. Read size, dimensions, and duration before processing.
8 samples help test tiny images, high-resolution images, alpha channels, and hard-to-compress assets.
Blue Sky PNG is a Portable Network Graphics sample based on Wikimedia Commons, 512 x 384. It can be used to test downloads, parsers, previews, and file type detection.
01-blue-sky.png8c4e8b9755c9a7a830220dbc1976923c1b25433377773567ed456ce64b6f5890
Flower Garden PNG is a Portable Network Graphics sample based on Wikimedia Commons, 640 x 360. It can be used to test downloads, parsers, previews, and file type detection.
02-flower-garden.png936f1936e08d92332d322d1375d8bdce7acdbeb110659d7e56f0ba10eb9fe5c7
Navy Blue Sky PNG is a Portable Network Graphics sample based on Wikimedia Commons, 768 x 383. It can be used to test downloads, parsers, previews, and file type detection.
03-navy-blue-sky.png0135de555c0d98a165ea21adddbe53f41477c1e2009162dca0b80ce3891de225
Nature Sky PNG is a Portable Network Graphics sample based on Wikimedia Commons, 720 x 540. It can be used to test downloads, parsers, previews, and file type detection.
04-nature-sky.png7b34840dee4f5fecbea7aec51c9113ef7fcf4b08c38e21f3a9604d1b89f59513
Sky Landscape PNG is a Portable Network Graphics sample based on Wikimedia Commons, 768 x 576. It can be used to test downloads, parsers, previews, and file type detection.
05-sky-landscape.png55ef3c8803651b27f7cef6214dba60c1ca73ffe427c529acba4bd642d853a8ea
Blue Night Sky PNG is a Portable Network Graphics sample based on Wikimedia Commons, 960 x 640. It can be used to test downloads, parsers, previews, and file type detection.
07-blue-night-sky.pnge926f8cd9f981d98f256acaf82e2266733e7d8d1507861904b53ebf5508925d3
NASA Earth 2048x2048 PNG is a Portable Network Graphics sample based on Wikimedia Commons, 2048 x 2048. It can be used to test downloads, parsers, previews, and file type detection.
nasa-earth-2022.pngf2bf466a5173fec5b3e0492312138c026d83dcd1c5980c45383d6684d07aad0a
NASA Blue Marble PNG is a Portable Network Graphics sample based on NASA Image and Video Library, 640 x 640. It can be used to test downloads, parsers, previews, and file type detection.
nasa-blue-marble-2012-east.png245e1a4eecaf262b7bbab32320b42e80b378ecf89f1642f6b36df4c77f543056Portable Network Graphics files begin with the byte signature 89 50 4E 47 0D 0A 1A 0A (".PNG...."). Detect the format by reading these leading bytes rather than trusting the file extension alone.
The MIME type for Portable Network Graphics is image/png.
Portable Network Graphics files use the .png extension. The extension is a convention only and does not guarantee the file contents, so combine it with signature and structure checks.
