With simple CSS3 code, you can create rounded corners, without needing to crop images with Photoshop. Moreover, you can even use an image as borders.
Rounded corner (IE9+,Firefox25+,Chrome31+,Safari7+,Opera18+,iOS3.2+,Android2.1+)
Rounded corner is trendy. In the example below, border-radius creates four circular segments(or rounded corners) with a radius 25px. If you specify a bigger radius, the four rounded corners are bigger.