Syncing Color

• Open file "images.jpg" and "guilin cave-2.jpg".
• Match the width of two files: go to image> image size> change the height.

• Open file> new.
• Move both files to a new screen by clicking the move tool (at the tool box)> drag the file (use crop tool if necessary). 

• Then at layer 1 (left picture), go to Image> Adjustment> Match Color. 
• At Target, will being written that layer 1 as a target image that having color adjustment. 
• At Source, select layer 2 (right picture). 

• Click OK. 

• Move layer 2,so that the little part of layer 2 is above layer 1.
• At the tool box, click eraser tool. Brush Set: 15, Flow: 20, Opacity: Adjust. 
• Erase line between layer 1 layer 2. 

• Here's the result. Compare with the initial image. 

 
Easy, huh? You can use this technique in various occasions. For instance, if you want to make banners and so on.