Issue with locating saved photos from Mac

Hi,

I have had a WD external hard drive for over a year now and I haven’t had any problems until now.  The problem I have now seems to be very strange and is very confusing to me.

What I usually use my hard drive for is saving photos from my camera.  I have taken a ton of photos over the last year and have backed them up on my hard drive many times.  Now, after not using it for a while, I decided to track down the full size version of a photo to email to someone.  Well, I couldn’t find the photo. 

After some investigation, I have discovered that the files that I saved all all there (ex. my friend’s photos are in a file called “Morgan and Lori”) but when I open the file it is empty.  No photos, just the folders.  It turns out that there are a lot of folders that should have photos in them, but they are empty.

On top of that, I save videos as well.  Well, some of the folders that should contain photos and videos from a certain session don’t have the photos but have the videos.  So, it seems like the videos are saved but the photos are no where to be found.

I have smaller versions of the photos saved to flickr, but without the originals I am kind of limited.  Where did they go?  I am sure that I’ve looked through them before. 

Do I need to do some sort of recover?  Any advice would be great.  Also, if you need more info let me know.  Thanks!

How did you backup your drive?  And what’s the images format?