Color distortion when rotating image

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Problem
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An user reported an issue via e-mail that using the `rotate` method causes 
color distortions in the resulting thumbnail.

When not using the `rotate` method, the thumbnail does not exhibit color 
distortion.

Note
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The issue seems to occur when a certain type of JPEG image is being rotated. 
Therefore, the problem may lie with the `Rotation` class. (And possibly other 
`ImageFilter` classes as well.)

Original issue reported on code.google.com by coobird...@gmail.com on 27 Aug 2011 at 2:41