Okay so I'm dealing with a picture of a tree. The whole background is white and I need to get rid of the thousands of little white background areas in between the leaves. Is there a way to sample the value white and then delete the rest of the white in the picture? Thanks.
May I suggest that you work in a mask... I find it to be much more flexible incase you make a mistake...
Plus, lets say you remove the edges BUT they are too hard... If you Don't have a mask it will be hard to blur the edges but not the actual image. With a mask, you don't need to worry about blurring the image, only the mask. It is non destructive.
And to make it permanent, you can just drag it to the trash and select "Apply Mask"