Create a new document and fill it with black using the Fill tool (fill). Open the channels palette (Channels) and create a new channel. Name the channel any name – for example, Square.
Click on the toolbar, Rectangular Marquee Tool, hold Shift and draw a square on 90% of the area of your black paper. Fill the square using the fill tool with white color and then, keeping the active selection in the middle part of the document, open the filter menu and apply to the selected area Gaussian Blur filter with a radius of 25.
Open menu Image -> Adjustment -> Levels and adjust the levels, combining both slider to the left, setting the Input levels to 0, 1.00, 255. Thus, you get a neat white shape with rounded edges, outlined with a black frame.
Finish creating frame – hold down the Ctrl key and click on the channel you have created a Square in the palette of channels (Channels). After that, selecting the channel, go to the layers palette (Layers) and create a new layer (Create New Layer).
Pour any color of the preserved selection – you now have a blank image with beautiful rounded edges. You can put this in a frame any photo. Similarly, you can create a narrower and a wider frame, by varying its size and shape depending on the type of photo and its size.