Major brightness/gamma changes in all imported images

[cammy8580]

Upon importing any texture into arctool, the texture in question seemingly will shift brightness in such a manner that becomes comical.
You can note that the chest seam has become much more noticeable due to the head texture being shifted in gamma.

The texture in the second image is only slightly modified, and retains the same brightness levels. Re-importing the texture simply messes with all brightness, and sometimes even causes weird compression artifacts that don't even happen after the image is exported. Only when imported into ArcTool.

Here are the two textures side by side.