Vignettes are often done in black to pull attention to the center of an image. Generally an ellipse, circle or rectangle is used.  But white can also used to gently feather the image into the border.

1. Pick a photo with room at the edges fo a vignette.

2. Duplicate background layer by dropping to new layer icon in the Layers palette.

Click on Background layer

Ctrl – A to select all

Edit – Fill – White

Ctrl – D to deselect

3. Click on Background Copy layer to make it active.

Using lasso tool, draw a loose curving line to designateedge of vignette. Set the Feather amount in the option bar to approximately 60 for small images, 200 for large images. You will want to experiment with this on different size images to find the look you like best.

Ctrl – Shift – I to invert your selection.

4. Once you have the border selected, click on Edit – Cut. You will have a nice soft border as shown below. You can add a Text layer with your signature or copyright too.