It is possible to replace colors in Photoshop, and sometimes it can be used to create excellent effects.
Open the photo you want to replace colors in Photoshop.
Now go to the Replace Colors Dialog Box (Image > Adjustments > Replace Color).
Now, go over your image, and select a color you want to replace.
Set the fuzziness up to an appropriate value. Fuzziness will allow more colors around your selected color to also be included in the replace.
Now it is time to actually replace the color with a new color, or "Result". In the lower portion of the Replace Color Dialog box, one can set the hue, saturation, and lightness of the replacement color.
To select more than one color, one can hold the shift button on the keyboard, while selecting more areas of the image. To apply a replacement, press OK.
