It works fine in OpenGL because ENB modifications only work in Direct3d. Whenever you take a screenshot in-game, Ogre does a render-to-texture and saves that to file; the ENB is probably modifiying that buffer to do its ENB stuff. It looks to me like a gaussian filtre is being applied, so maybe if you disable some features in your ENB (i.e. bloom, motion blur) it won't modify it. Failing that, you might just need to get an external screenshotting tool and just capture the window that way.
