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Why is the download count not incrementing on my deviation(s)?
Deviations that are solely images are not downloaded in the standard sense of the word.
If a deviation that is submitted is a .JPG, .GIF, .PNG or .SWF file, then it is merely viewed online and the views increment, unless an smaller resized image deviation is also available for download at its original size, in which the download of that increments the download count.
Only files that are actually downloaded (e.g. .ZIP, .RAR, .7Z, .WS, .WBA, etc.) have the download count incremented.
This generally means that skins and themes will see their download count increment while images will not.