Below is an example image, where the top of the girl's head is cut, and pixels are missing.
Is there an easy way re-create the pixels in that section properly ? Thanks.
There is no automated method which will generate artwork, matching existing pieces, where no art exists.
One needs to recreate any missing portion manually. Whether that means you draw areas which are missing, or utilize tools such as the *Clone Stamp Tool, or things such as Content Aware fill... it all must be done manually.
There's no "button" or "command" that will generate matching artwork from scratch.
