Unfortunately you are somewhat at the mercy of the Youtube iframe and the Flash video player in it.
Do this as a test.
Open your page in IE (FF is not a problem) and "disable" the Flash player.
In main IE browser menu...Tools/Manage Add-ons/Shockwave Flash Object.... "Disable".
Then test your page... images work just fine.
The problem is not your "container" code... but it's Flash content.
Most like it has to do with the wmode used for the Flash player... from an old article (there are now more wmodes):
Window Mode (wmode) - What's It For?There are three window modes.
In windowless modes (like opaque), Flash Player doesn't have a hWnd. This means that the browser tells the Flash Player when and where to draw onto the browser's own rendering surface. The Flash movie is no longer being rendered on a higher level if you will. It's right there in the page with the rest of the page elements. The Flash buffer is simply drawn into whatever rectangle the browser says, with any Flash stage space not occupied by objects receiving the movie's background color.
plus tons of other examples on line.
Thank you for your help Adninjastrator for your help after you explained the issue I found out through research that if you add "?wmode=opaque" to the end of the You Tube URL then it fixes the problem.
Now I'm trying to get the controls button images working.
Fixed all issues my image folder had a CAPITAL i (Image not image).
Thank you everyone