//preload images...
var g_egg = new Image
g_egg.src = "images\\green_egg.gif"
var f_egg = new Image
f_egg.src = "images\\fried_egg.gif"

var roll_ok = document.images

function m_over(id){
   if(roll_ok) document.images[id].src=g_egg.src
}

function m_out(id){
   if(roll_ok) document.images[id].src=f_egg.src
}