What happens to the layers of an image file when it is saved as a JPG?

When an image file is saved in the JPG format, the layers of the image are flattened into a single, composite image. This means that any separate elements of the design, such as text, shapes, and different graphics that may have been on individual layers, are merged together into one uniform layer. This flattening process is a key characteristic of the JPG format, resulting in a file that is optimized for smaller file sizes and faster loading times, which is ideal for web use and sharing.

Once saved as a JPG, the individual layers cannot be edited separately anymore, as they are no longer distinct elements. This highlights the JPG format's design, which prioritizes compression and compatibility over the ability to edit individual components later on. In contrast, formats like PNG or PSD retain layer information, allowing for future modifications without losing the structure of the design.