Best way to fill an image placed into a larger box without creating artificial edges?

1. Which tool is used to fill an area of an image or entire image with a range of Colours?

Which tool is used to fill an area of an image or entire image with a range of Colours?

Select the Paint Bucket tool (G) from the toolbar. If you can't find the Paint Bucket tool, click and hold the Gradient tool to show the other related tools, and then select the Paint Bucket tool. In the tool options bar, choose to fill the selection with the foreground color.