Iterates over the images inside the div and scales its id:

 $("div img").each(function(i){
   this.id = this.id + "_" + i;
 });

Before

 <div><img id='me'/><img id='me'/></div><img id='me' />

After:

 <div><img id='me_0'/><img id='me_1'/></div><img id='me' />