Flip / mirror an image horizontally + vertically with css

Try this:

.img-hor-vert {
    -moz-transform: scale(-1, -1);
    -o-transform: scale(-1, -1);
    -webkit-transform: scale(-1, -1);
    transform: scale(-1, -1);
}

Updated fiddle: https://jsfiddle.net/7vg2tn83/1/

It wasn’t working before because you were overriding the transform in your css. So instead of doing both, it just did the last one. Sort of like if you did background-color twice, it would override the first one.