Layer function is introduced from Photoshop 3.0, and to Photoshop CS, layer function has been considerable development and improvement.

Synthesis results in the previous figure drawing, it is often the first object drawn in a number of glass sheets of paper, then put together to produce synthetic effects, so the effect of making it very easy to adjust the map. Like a cellophane layer, but its function is more powerful than the cellophane. It not only can save the image information, but also through the use of layers of synthetic patterns, layer opacity and layer adjustments in order to adjust the object layer, fully embodies the characteristics of digital images.