Set teh valid mime and human types on the dimension upload widgets.
Better dimension notes.
 * real mulitplication symbol
 * better handling of when only width or height is set including dropping the plural on "Maximum Dimensions..." and explicitly stating which dimension the maximum size applies to.
Better error message from @nburka.
Add getDimensionUploadWidget method, and use it whenever accessing the dimension uploads.
Drop an IE6 style copied from very old code.