What are magic bytes?

Magic bytes (also called file signatures) are specific byte sequences at the start of a file that identify its format. For example, JPEG files always begin with FF D8, and PNG files begin with 89 50 4E 47. These are more reliable than file extensions, which can be renamed.

Which formats can be detected?

The tool detects JPEG, PNG, GIF, WebP, BMP, TIFF (both endianness), ICO, AVIF, and SVG (as XML text). Any unrecognised format is reported as unknown.

What does a format mismatch mean?

A mismatch means the file extension does not match the actual file format. For example, a file named photo.png that is actually a JPEG. This is common when files are renamed without conversion.

Image Format Detector

Detect the true format of any image file by reading its magic bytes — catches misnamed files instantly.

Drop any image file here or click to browse

The actual format is detected from file magic bytes, not the filename

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FAQ

What are magic bytes?: Magic bytes (also called file signatures) are specific byte sequences at the start of a file that identify its format. For example, JPEG files always begin with FF D8, and PNG files begin with 89 50 4E 47. These are more reliable than file extensions, which can be renamed.
Which formats can be detected?: The tool detects JPEG, PNG, GIF, WebP, BMP, TIFF (both endianness), ICO, AVIF, and SVG (as XML text). Any unrecognised format is reported as unknown.
What does a format mismatch mean?: A mismatch means the file extension does not match the actual file format. For example, a file named photo.png that is actually a JPEG. This is common when files are renamed without conversion.

The Image Format Detector reads the first few bytes of an uploaded file (its "magic bytes") to identify the true image format, independent of the file extension. It detects JPEG, PNG, GIF, WebP, BMP, TIFF, ICO, AVIF, and SVG. The tool also reports file dimensions and size, and highlights any mismatch between the filename extension and the actual format.