Tip:
Highlight text to annotate it
X
Go to open.
Select a screenshot.
Go to Image > Adjustments > Curves
Experiment with curves to fit the lighting.
Go to Image > Adjustments > Vibrance
Bump it up however much you want depending on the screenshot.
Go to Filter > Sharpen > Sharpen Edges
Go to Image > Image Size
Make it 800 x 452
To make a border, click the Rectangular Marquee Tool.
Outline the entire screenshot.
Go to Edit > Stroke
Experiment with the width and color, making sure the location is always clicked inside.
Now go to File > Save As > Save as PNG