What is a drawback of flattening an image?

Flattening an image in Photoshop combines all the layers into a single background layer, which can significantly limit the flexibility for future edits. When an image is flattened, the individual layers that might contain separate adjustments, effects, and edits are merged into one; this means you lose the ability to modify those elements independently. If changes need to be made later on, such as color adjustments, text edits, or alterations to specific effects, they become much more complex, as you'd essentially need to start over or create new layers from scratch.

While it's true that flattening can simplify some aspects of the image (like reducing file size and improving performance for display), this process inherently restricts the array of adjustments that can be made later, thus limiting the works' overall flexibilty. Therefore, understanding the implications of flattening is crucial for making informed choices in the editing process.