Invert the colors of an image layer
In Windows > Editors > Canvas Layer Editor 
, choose Edit > Invert layer.
This tool inverts the RGB colors in the image. For example, red (255,0,0) becomes cyan (0, 255, 255).
This tool does not affect Shape layers.
Note:
When applied to a mask layer, or invisibility mask layer, it swaps the masked and unmasked regions, just like Edit > Invert Mask or Edit > Invert > Invisibility Mask.