Little Problems: Fixing Common Problems - The Adobe Photoshop CC - page 443

Step Nine:
Now, go to the Layers panel's flyout menu and choose Flatten Layers (you have to flatten
that Smart Filter layer now to do this last step). Get the Magic Wand tool (press Shift-W
until you have it) from the Toolbox, and click in all those white gaps at the top, bottom,
and sides to select them (press-and-hold the Shift key to add to the selection). Go under the
Select menu, under Modify, and choose Expand . Enter 4 pixels and click OK to expand
your selected area by 4 pixels. Now, go under the Edit menu, choose Fill , and from the Use
pop-up menu, choose Content-Aware Fill . Click OK to fill in those areas, and then press
Command-D (PC: Ctrl-D) to Deselect. Below is a before/after.