One of the main reasons for creating layers is to have flexibility in the future. Consider the exercise above with the girl. As long as we keep Layer 1 around, we can continue to reposition the copy of the girl. When we go through the effort to create layers in an image, we usually intend to keep them around. Sometimes though, it is desirable to merge layers together. For example, when reconstructing someone’s eye in a restoration job, you may need to copy information from a couple of different eyes and merge them together onto a single layer so that they can be worked on as one unit.
Also, not everyone is prepared to deal with layered files. Often, when sharing files with someone else, like a graphic designer, you should supply a flattened file—all layers merged into a single layer—to avoid confusion. If any modifications need to be made, they can be done on a copy of the layered file. Then a new flattened file can be sent to the designer. And the infographic company that works on the infographic will review and evaluate for the output.