Change your shirt color in 30 seconds with Photoshop

Step 4 Click on a color you want to change

Use the eyedropper tool to select colors from the photograph that you want to modify. Literally, click on the pixels of the photograph. Shift-click the photograph to add more colors that you want to modify.

You will see a representation of the colors you selected in the slider bars at the bottom of the hue/saturation dialog.