background-image is shown in firefox and internet explorer diffrently

hi
i'd like to set background-image of submit button to a picture with gif extension
i set style="background-color:url(images/back.gif)" in input tag
with this work this button in firefox is shown correctly
but in internet explorer incorrect later set value attribute to " " so that this button is shown correctly in ie browser with this work button is shown in ie correctly but in firefox is shown repeated
what do i so that background-image is shown correctly in all browser?
note:i dont like have lable for button
another question is : i have a layer is website desgin that consist of flash element i'd like set that place under another layer i set z-index attribute less than another layer but is show on.
thank alot

re: background-image is shown in firefox and internet explorer diffrently

Did you type that correctly? It should be 'background-image'.