This method utilises CSS to position both images absolutely in the container and use CSS to set the z-index of the foreground image higher than the background image. Looking for css and html tricks to overlay text above image or background image here is code resource which help you to get this job done easily in no time. Also check out: Image Overlay Slide, Image Overlay Zoom, Image Overlay Title and Image Overlay Icon.
The process for doing this is fairly straight forward.
I often come across questions which involve how to overlay images in a web page. Put images on top of another image using HTML - CSS, placing one image on top of another CSS - HTML, Displaying IMAGE Over Another IMAGE, Insert image on.