In photoshop, the information pannel give you that. I’m pretty sure it’s also possible in Gimp.
Or you can make your own tool ! I made you a small example in jsfiddle : http://jsfiddle.net/zz3Rh/19/
The html :
<div id="image">image</div>
coordinates :
<div id="coordinates">0</div>
The css :
#image{ height:350px; background:#c00;}
The js (with jquery loaded) :
$(function(){
$(document).mousemove(function(e){
$('#coordinates').html('x: ' + e.pageX + ' y : ' + e.pageY);
});
})
BECAUSE WEBTOOLS ARE THE FUTURE !!!! 🙂
(and because this is a forum for developpers)