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I have a weird image in my notebook. If I do ImageResize to it. The pixel values of this image is changed.

enter image description here

Sorry, I can not share this image directly. As you can see, exporting it and then importing it back will not reproduce this behavior. So I have to share this notebook here.

What is wrong with this image? How to correctly ImageResize this image without changing its pixel value (Of course, I can not stand exporting and importing)?

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  • $\begingroup$ I don't see why you need to share the notebook file instead of adding code as text as is customary, and a link to the original image. I may be overly paranoid, but I still do not like opening potentially executable files from the internet. $\endgroup$
    – MarcoB
    Jul 25, 2023 at 14:58
  • $\begingroup$ @MarcoB Thank you for your comment. I already said in the post if I share exported image, and then you import it. You will not reproduce the weird behavior. $\endgroup$
    – matheorem
    Jul 25, 2023 at 15:03
  • $\begingroup$ @MarcoB By the way, will a Mathematica notebook run anything automatically when it is just opened without evaluating? $\endgroup$
    – matheorem
    Jul 25, 2023 at 15:07
  • $\begingroup$ Potentially, if it contains dynamic evaluations. $\endgroup$
    – MarcoB
    Jul 25, 2023 at 15:09

1 Answer 1

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Compare Information[img] and Information[Import["D:\\1.png"]]. You will see that the data type of original image is Real32, while exporting/importing to .png make it Bit16.

You can either change the data type of your image:

ImageResize[Image[img, "Bit16"], 100] // MinMax
(* {0., 1.} *)

or use different resampling method for resizing (see documentation for ImageResize):

ImageResize[img, 100, Resampling -> "Nearest"] // MinMax
(* {0., 1.} *)
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