[removing semi transparent pixels(or changing their value)]

If there were a option like "ignore opaque pixels" that would be perfect for me. Looks very useful plugin btw.

[removing semi transparent pixels(or changing their value)]

I want to remove only semi transparent pixels in a image. I want to keep others without changing them. How can i do that?

And is it possible to increase/decrease of all semi transparent pixels at one time?

For example: When i choose the increasing tranparency-alpha value at 20

if a pixels transparency is 120, it will be 140

if 75, it will be 95

if 255, keep it same

if 0, keep it same

sorry for bad english.