Discourse loses the top/bottom pixels when generating thumbnails

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I wonder if it depends on screen size, with different assets being served to different clients.

Having a quick look at the post/image above via F12, I found two assets, plus the original image:

  • Original image (1416 x 946) /original/3X/e/2/e2c5f032e18fa374c0593af71cf25d3499826289.png, which is untouched. Direct URL

  • Smaller version (1380 x 920) optimized/3X/e/2/e2c5f032e18fa374c0593af71cf25d3499826289_2_1380x920.png, which has (almost) invisible top and bottom edges. Direct URL

  • Even smaller version (640x460) optimized/3X/e/2/e2c5f032e18fa374c0593af71cf25d3499826289_2_690x460.png, which has no bottom border at all, but has the left, top and right borders. Direct URL

There might be some ImageMagick arguments to tweak the scaling algorithm and how it handles pixels at the edges, although any change could of course make other situations worse while improving this one.

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