An image array can have the expected dimensions and still contain the wrong channel order. This is an implementation mismatch that a simple visual comparison can help expose.
OpenCV's colour-conversion documentation distinguishes BGR, RGB and other representations. OpenCV — colour.
Check the boundary between tools
For a product-photo pipeline, confirm what each decoder returns and what the next component expects. Do not assume that every library uses the same convention. Preserve an identifiable reference image for a sanity check.

Test the complete route
Inspect the actual input after preprocessing, not only the original file. A colour-sensitive task can fail even when the saved source photograph is correct. Record the conversion explicitly so later maintenance does not reintroduce the mismatch.

Source reviewed 25 October 2026. Interpretation and original diagrams: PLUSHIP / Qunhe. Examples are illustrative.
Related reading
A Pipeline Keeps Learned Preprocessing With the Model
Scaling Should Reflect the Distribution of the Actual Input
