Color model and color profile are different things
RGB, grayscale, CMYK, and YCCK describe how pixel components are represented. An ICC profile describes how those values map to a color space or output condition. A file can reveal one without fully specifying the other.
What JPEG structure can tell you
JPEG frame/component metadata can reveal grayscale, ordinary three-component RGB/YCbCr-family imagery, or four-component CMYK/YCCK-family data. Adobe APP14 and ICC APP2 segments provide additional evidence.
- Four components are a strong sign that the JPEG belongs to the CMYK/YCCK family.
- Three-component JPEGs are commonly decoded into RGB for browser display.
- An embedded ICC profile is stronger color-management evidence than a filename or extension.
PNG uses explicit color-management chunks
PNG can include iCCP for an embedded ICC profile, sRGB for standard rendering intent, and related chromaticity/gamma chunks. The image color type separately describes grayscale, indexed, RGB, and alpha structure.
Why profile detection is not soft proofing
A printer can require a specific profile for a particular press, paper, ink, or lab workflow. Detecting an ICC profile does not prove that it is the correct destination profile or that the file has been converted correctly.
- Ask the printer for its required color space/profile.
- Keep the original before converting color spaces.
- Use a color-managed editor for actual profile conversion and soft proofing when needed.
Inspect metadata locally
OpenFileTools reads a bounded portion of the file in the browser and reports structural evidence. No image or profile data is uploaded and no automatic color conversion is performed.