A mixin for doing text-indent image replacement

image-replacement.scss

%screen-reader-text {
	text-align:left;
	text-indent:-9999px;
}
@mixin background-image-dimensions($image) {
	width:image-width($image);
	height:image-height($image);
	background-image:url($image);
}
@mixin image-replacement($image) {
	@include background-image-dimensions($image);
	@extend %screen-reader-text;
}