HI arthur ,
it can be acheieved by CSS .
just take your Large image in a parent DIV , gve its a iD. then assign its css
position:relative .
now your smaller image will be in a div with style position:absolute .and give this
div top:200px nd left:200px; like this to make this in center .
#div-1 {
position:relative;
}
#div-1a {
position:absolute;
top:0;
right:0;
width:200px;
}
your div-1a will be in div-1 as a child and you can locate this to center .
you can do this dynamically too from code behind .