Retain the 8 bit format after rotation

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magick
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Post by magick »

Add -colors 256 to your command line to create a colormapped BMP image.
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anthony
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Post by anthony »

If you do not want -rotate to add extra colors to your image, but only use existing colors (some image degrading can occur) then you can use -interpolate nearest-neighbour setting before rotating. This is a new addition to IM and not yet fully documented in IM examples.

Also rather than -colors 256, you can re-map the colors to the original set of colors using
-map original.bmp. For more info on color reduction see the IM examples section of "Color Quantization and Dithering".
Anthony Thyssen -- Webmaster for ImageMagick Example Pages
https://imagemagick.org/Usage/
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