.container {
position: relative;
}
.img-pos {
position: absolute;
top: 10%;
left: 5%;
}<div class="container ">
<img src="http://www.coupondiscountblog.com/images/An-Easy-Guide-to-Programming-in-C-Second-Edition.jpg" />
<img src="http://www.coupondiscountblog.com/images/C-Primer-Plus-5th-Edition.jpg" class="img-pos"/>
</div>