iphoto in Dropbox

I am sooo nervous about losing our photos and I have many duplicates. I have used a little bit of duplicate annihilater but it freezes up when it tries to do 15,000 photos and I am afraid to set it to trash them so I have just labled them. So now I have upgraded Dropbox to 50gb and packrat with it. Now, my ? is how do I pu my iphoto photos into Dropbox. I have never understood why you cannot just go to your pictures in an iphoto file and transfer them but iphoto seems to hide the real pictures. Does anyone know how to do this? I think I need t upgrade to Aperture but am scared off by reviews of people losing ALL when transfering from iphoto to Aperture.