Try the following on the Expert tab:
- Open picture file
- Duplicate background layer
- Add a blank layer between the background layer and the background copy layer.
- Fill the blank layer with white. (Background layer is at bottom, white layer in the middle, background copy layer is at the top.)
- On the top layer, make your selection with the Elliptical marquee tool, to embrace that which you wish to retain. Note that you can nudge the ellipse with the arrow keys on the keyboard.
- Go to Select>Inverse, then Select>Feather - - try 25 (experiment)
- Hit delete on the keyboard
- Press CTRL+D to get rid of the marching ants