You can use the Eyedropper tool  to add colors from imported graphics to your document, or to apply them to objects in your document. This is useful for coordinating layout colors with images.

For best results with color separations, you may want to make sure that color names, types (such as spot and process), and models (such as RGB and CMYK) of the colors sampled in InDesign are consistent with the color definitions in the imported graphics. If you’re not sure about the best settings to use, consult with your prepress service provider.