Let’s take an example picture (Original.png).
I convert it to DDS, then extract it with IrfanView back to common graphical format (Extracted by IView.png).
It now has changed coloration and is darker. The effect is not produced by conversion to DDS, as can be seen if make the same with some other appropriate program (I used now GIMP2.10.24, in the past it was nVidia utility).
The effect is not very pronounced with this particular image I choose as illustration, but sometimes tone change was very perceptible. Also, it is quite easy to see the difference if looking at the corresponding histograms (Histo Original.png, Histo Extracted by IView.png, Histo Extracted by GIMP.png), the shrinkage of the graph to the left is obvious.
I am using Win 10 and Ifanview v. 4.57 (both 32 and 64 bits) now, but I believe it is irrelevant, as it all was the same 15 years ago.
I convert it to DDS, then extract it with IrfanView back to common graphical format (Extracted by IView.png).
It now has changed coloration and is darker. The effect is not produced by conversion to DDS, as can be seen if make the same with some other appropriate program (I used now GIMP2.10.24, in the past it was nVidia utility).
The effect is not very pronounced with this particular image I choose as illustration, but sometimes tone change was very perceptible. Also, it is quite easy to see the difference if looking at the corresponding histograms (Histo Original.png, Histo Extracted by IView.png, Histo Extracted by GIMP.png), the shrinkage of the graph to the left is obvious.
I am using Win 10 and Ifanview v. 4.57 (both 32 and 64 bits) now, but I believe it is irrelevant, as it all was the same 15 years ago.
