How can you change the background color of a layer in Photoshop?

Changing the background color of a layer in Photoshop can be accomplished effectively by double-clicking the layer thumbnail. This action brings up the Layer Style dialog box, where you can apply various styles to the layer, including a solid color overlay. By selecting the color overlay option, you can set the background color for that specific layer. This method allows you to change the visual appearance without permanently altering the original content of the layer.

In contrast, simply using the Fill Tool is not the only method for changing a layer's background color, as it primarily fills selection areas rather than altering the layer's color directly. Adjusting the layer mask affects the visibility of parts of the layer rather than changing the overall color. Flattening the image merges all layers, which can finalize the appearance but does not allow for easy modification of individual layer colors afterward. This makes double-clicking the layer thumbnail the most effective approach for changing the background color in a non-destructive manner.