Loop for multiple gifs?

So I'm new to programming for web. Here's what I'm trying to accomplish. I have 6 different gif's I'm wanting to use in a loop. Each gif speed varies. I want to start with a still image of the gif, pause for 30 sec, then run through each gif file for lets say 3 seconds each. After running the last gif, I would like it display the still (.png) for 30 seconds again before starting back up. What's the best way to accomplish this? PHP, html, javascript? My file path from root is "images/gif" then my 6 gif files and one png. one.gif, two.gif, etc. Your help with this is greatly appreciated!