This is something that can easily be fixed.
All you need to do is go to Pictures in Finder then under that you will see "Aperture Library" with what looks like a white cube with the front of a lens on it. Drag that to the trash and delete it. Then open Aperture again and when importing images, on the left hand side make sure to import them as referenced files and to leave them in their original location.
Doing this will just create a reference to the image file which will save you a lot of space. If you decide to purchase aperture you can reference all of your files to hard drives to save your HD space on your computer, as well as easily back them up to another drive because they are just pictures in a folder that can be copied.
cheers this really helps!