Here is a great time saving trick to use in Lightroom if you love the look of rounded corners for your photographs.
Go to POST CROP. Then change settings to:
Amount = +100
Midpoint = 0
Roundness = -100
Feather = 0
The results are shown here. Play around with the midpoint and roundness to change the look.
Here is result changing Roundness to -79. Have fun rounding your corners too!!!