Drop Shadow shows on some images and not others

I have added drop shadows via css code.  It works great on most of the site and really adds a little depth, which I was looking for.  However, it would not work on images that have any animation, so I removed the animations I had, as well as will not show on the thumbnails on my portfolio page.  I thought maybe if I could remove the title of the images from showing on mouseover that it may work, but it seems you cannot remove the title.  Does anyone know how I can add the drop shadows so they work at the very least, on those thumbnails on the portfolio page, and if able to do it on images with animations or other effects, that'd be great.

You can see one screenshot of a page I created with images that was not using the portfolio pages with drop shadow.  The other is a screenshot of the portfolio page without drop shadow which looks a bit flat.