Screen resolution detection?

[664927d700168xdiesp]

Is there a trigger or script that fires according to screen resolution? I would like to add a hud overlay on the "far left" of the screen (which is actually an item plastered on the player's face, like the compass), but how far left should be determined by the current resolution. The problem is that an overlay that works in 16:9, won't show up on 4:3.