or you could do both randomly on the fly like this
heres one image
http://kotiki.ru/funny/0.jpg
and another pic
http://www.buffalorange.com/images/awards/funny.gif
now we will combine them together using the following liking code
(notice both image urls contained within the url
tools.webspacemania.com/free/freehttp://kotiki.ru/funny/0.jpghttp://www.buffalorange.com/images/awards/funny.gif.png
the result is
