"Disk image" = "partition" ?

I created some extra "disk images" with file system type ext3, but can't find them, and don't know what they are called. There's the original udba device, and the ubdb (i think) for swap. What are the new "images" called. What command should I use to "see" all of the disk images. I tried df and mount. I know the new images won't mount automatically unless i list them in fstab, but I don't even know what they are called.