>>>see visual #1

Open an image in Adobe Photoshop.

>>>see visual #2

Duplicate the layer your picture is on (I usually just right click the layer and select the 'Duplicate Layer...' option)

>>>see visual #3

Now go to Filter > Blur > Gaussian Blur and set the radius to about 4.0 pixels.

>>>see visual #4

Set the layer mode to Overlay.

>>>see result

And your done!

You can also experiment with the Gaussian Blur's radius, layer mode, and opacity and set it to your liking.