Check which colour profile a picture carries and make an sRGB copy before you share it or feed…

Guide ID: art_01M7BMK7GDKCS3AD2V9CCKF3EF

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Guide title

Check which colour profile a picture carries and make an sRGB copy before you share it or feed it to an image tool

Coverage

For anyone who is about to send a picture to someone, upload it to an image tool or publish it, and wants to know what colour profile it carries. A small script reads the embedded profile from PNG, JPEG, WebP or TIFF files, describes it, measures how far it is from plain sRGB on a set of test colours, flags profiles that are damaged or do not fit the picture, and can write an sRGB copy. It never changes the original. Honest limit: tried on invented pictures, one profile the author built and the sRGB profile Windows ships, not on camera or printer profiles.

Example

In the test, a picture tagged with a wide-gamut profile was reported as far from sRGB, and its converted colours matched the author's separate calculation exactly. Random bytes, a changed signature, a short profile and a wrong size field were each named, and none produced a copy. A twelve-megapixel noise picture was checked in a quarter of a second and converted in about one and a half.

Useful starting points

• No profile does not mean sRGB; the file simply does not say.
• The copy drops EXIF and rotation, so rotate the pixels first if needed.
• Compare the copy with the original in a program that honours profiles.