You can't just drag and drop the volume. There are tons of hidden files on the volume. Just dragging it over will not work. You should check the image file you made too. It probably is not the exact same size (meaning it did NOT copy everything over).
If you still have all the data on the original drive (not the image file you created), then you can put that drive in the USB external enclosure, install the new drive in the computer and then run the Migration Assistant. This will get all your info of the external drive and onto the new drive.