From http://stackoverflow.com/questions/7415872/change-color-of-png-image-via-css

new_gist_file.css

/*Filter styles*/
.saturate {-webkit-filter: saturate(3); filter: saturate(3);}
.grayscale {-webkit-filter: grayscale(100%); filter: grayscale(100%);}
.contrast {-webkit-filter: contrast(160%); filter: contrast(160%);}
.brightness {-webkit-filter: brightness(0.25); filter: brightness(0.25);}
.blur {-webkit-filter: blur(3px); filter: blur(3px);}
.invert {-webkit-filter: invert(100%); filter: invert(100%);}
.sepia {-webkit-filter: sepia(100%); filter: sepia(100%);}
.huerotate {-webkit-filter: hue-rotate(180deg); filter: hue-rotate(180deg);}
.rss.opacity {-webkit-filter: opacity(50%); filter: opacity(50%);}