> Assistive technology can't magically detect that your image has low > contrast and provide a better image. I don't think that AT even comes > into play as high contrast mode is handled by the OS. High contrast > mode is not the same as choosing a monochrome display. On Windows, the > default high contrast display is mostly white on black, but there are > still colors, and text is larger. On OS X, high contrast mode is just > extremely contrasty with lots of detail getting washed out; you can > separately choose to use grayscale and/or invert colors. > > Authors may want to provide images with lots of detail, but fall back > to images with less detail and/or larger objects/text in the case of > high contrast mode.
In that case it sounds like we need somthing like the -ms-high-contrast [1] media feature needs to become a standard. [1] http://msdn.microsoft.com/en-us/library/ie/hh771830(v=vs.85).aspx
