A simple example of how to do that in Gimp (using gausian blur instead of scale, but it is the same bug) would be this. The correct way would be to transform the image to a linear scale before applying the filter and then restoring it the exponential one for display.
In real photos it will be less noticeable then here, but it will still happen. Thus when you scale things or apply other filters the brightness will be messed up. The problem is that the browser or the image application assumes that the brightness is stored on a linear scale, while in reality its stored exponential one. Yes, the image is designed to exploit the bug in way that makes it very obvious that the scaling is wrong, but no, the gray rectangle is not the correct solution. IMO, what it actually means is that the so-called image is deliberately designed to be as catastrophically horrible as possible when scaled down.
I believe this has happened since the first versions of these programs, maybe 20 years ago." The degradation is often faint, but probably most pictures contain at least an array where the degradation is clearly visible.
#GAMMA CONTROL IN GIMP FOR MAC OS#
(These exceptions have subsequently been reported - this software does not suffer from the problem: the Netpbm toolkit for graphic manipulations, the developing GEGL toolkit, 32-bit encoded images in Photoshop CS3, the latest version of Image Analyzer, the image exporters in Aperture 1.5.6, the latest version of Rendera, Adobe Lightroom 1.4.1, Pixelmator for Mac OS X, Paint Shop Pro X2, and the Preview app in Mac OS X starting from version 10.6.) Photographs scaled with the affected software are degraded, because of incorrect algorithmic accounting for monitor gamma. The problem exists across three different operating systems: Linux, Mac OS X, and Windows. All software tested has the problem: The Gimp, Adobe Photoshop, CinePaint, Nip2, ImageMagick, GQview, Eye of Gnome, Paint, and Krita. Wescotte writes "There is an important error in most photography scaling algorithms.
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