No. Whenever you edit or enhance a photo, you're working on a copy. If you select As a copy (located toward the right side of the page) before you save, you'll be able to view both versions in your album.
However, if you select As a replacement, the new, edited copy will be saved in your album, and your original photo will not be visible. To view your original, return to the Fix & enhance page (through the Edit link under the Tools menu) and click Revert to original photo (under the Fix tab).