CSS .Hover Image Loading Slow

I have a submit button that changes when the user hovers his mouse over it. Right now the image is taking a while to load and you get a 开发者_开发问答half second where there is white screen instead of the other button. Is there anyway to improve this using just CSS and HTML or do I need to do some JS work?

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Use a sprite image, and then toggle background position on hover. That ensures that the image being displayed on hover has already been downloaded.

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CSS Sprites

And load the css sprites when DOM is ready, this can sort of "preload" the image before user hovers on the submit button :)