There are a few ways to change CMYK to RGB in Photoshop. The first way is to use the color picker. To change the color of a pixel, select the color you want to change and then click on the blue or green button. The second way is to use the eyedropper. To change the color of a pixel, select the color you want to change and then click on the eyedropper icon. The third way is to use the keyboard shortcut CMD+R. To change the color of a pixel, type in CMD+R and then press Enter.
