The Image Color Picker samples pixels for a palette. An attractive swatch does not automatically produce a readable text/background pair.
Sample deliberately
Compare multiple pixels from a region, not one edge pixel. Anti-aliasing, compression, gradients and shadows can alter nearby values. Save the HEX or RGB value and source image so the sample is reproducible.
For brand assets, compare with the original design specification if available. Resizing and color management can make a screenshot sample differ from the intended source color.
Check the pair
Use the Color Palette tool to compare foreground and background. Evaluate actual text size, weight and interaction states. A pair suitable for a large heading may fail for small body text. Test light and dark themes separately and avoid using color as the only status indicator.
The WCAG contrast criterion explains text requirements. A passing color pair is one accessibility check, not certification of the whole interface.