The pachyderm's problem was that the color on the original image was a tad too bright for X-Com's palette, so closest color matching turned the red into pink and orange, which have higher brightness in X-Com. The original image does have that blueish background color, but it made it look washed out. By lowering the brightness a little and nudging up the contrast it converts to X-Com's palette much truer, and it's just a few minutes of pixel hunting to chase out the random green and pink pixels that pattern dithering likes to insert.