I agree with the previous posters as not relying on online backup as a primary source. Though, it may not be a bad idea if you're traveling and need to upload the photos somewhere for redundancy purposes. If your laptop is stolen, then you'll at least have the photos online to download when you get home.
Instead, I would get an external enclosure that can hold two hard drives and have them RAIDED. You can set it up as RAID 1, which is creates a mirror image of all your data. If one of your hard drive crashes, you have a secondary copy. Plug in a new hard drive, and you'll have two copies again. Of course, the downfall is you lose half of your space. More advanced external enclosures can create RAID 5, but you'll need at least 3 drives. It's a lot more complicated to explain, so you may want to do research on it if you want to go that route.