According the compatibility data referenced by Marcus,
background-size
is not processed properly in the browsers you list.
I don't think you can do anything about it. Not supported means not supported. I would recommend to slightly change design to avoid this style. Why?
The style
background-size: 100% 100%;
cannot be perfect anyway. Here is why: the causes stretch of the background image, which cause
re-sampling. There are problems with
any re-sampling in principle: the quality of image depends on the rendered size of the block element (or window) and can cause most ugly pixellation as the stretch grows. Even rendering performance could suffer. Again, you cannot fix compatibility unless you force custom CSS for different browser, which is also a problem.
Therefore I would recommend using
background-repeat
styles to tile your image. See, for example:
http://www.w3.org/TR/CSS2/colors.html[
^].
Good luck,
—SA