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Hi friends I am a geologist.

I have a geological map and I will edit it in a CAD program, but there are transparent pixels in the image file and my CAD program perceives it as a white background.

All I want to do is an image file that has been cleaned from all trimmed, transparent pixels.

Thank you in advance for your help.


  • Do you want to remove the white pixels or the tranparent ones?
    – LeoNas
    Feb 27, 2018 at 16:26
  • We have a little problem. Nobody here knows do you want to remove something from an image which is exporetd from your cad program. Or do you want remove something before you import to CAD? What you want to remove and what is allowed to be instead. You cannot remove the pixels (except by resizing) you can only redefine the color and transparency. There's no such thing as fully empty pixel, every pixel has some color (=RGB values) and degree of transparency. Before you specify, all answers are guesses, two first answers are both good guesses, I think.
    – user82991
    Feb 27, 2018 at 20:51
  • I've rolled back the edit that was made to the title until OP comes back to clarify their question.
    – curious
    Feb 27, 2018 at 21:12

2 Answers 2


If I understand what you're asking, here is one way to do it:

  1. Press Ctrl+Alt+Shift+S to bring up the "Save for Web" interface.
  2. Select "Ping-8" as the file type.
  3. Click on the color swatch that you want to be transparent.
    (White in this case)
  4. With the desired swatch selected, click the "Maps selected colors to transparent" option at the bottom of the Color Table window.
  5. Click Save.

List item


You can't remove those pixels, the image will always have an original rectangular size. The problem then lies with how the application you use renders the image. Have you tried other formats? Usually PNG carries transparency but maybe it you can provide the name of the CAD program you use we may be able to help.

  • Curious on the downvote? The OP's question title has been edited but it seems like the OP was originally asking to remove the transparent pixels, not the white that lies within the map.
    – curious
    Feb 27, 2018 at 16:17

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