Western Digital 500Gb portable hard drive

I'm in a major need of backing up all of the photos on my MacBook. With that in mind I purchased Western Digital 500Gb portable hard drive. A 500gb portable hard drive should keep me going for a while. The price of hard drive was o.k. for a shop purchase at £45 and the only point of note was the fact that I had to reformat it for Mac. A simple task but one to be aware of when plugging it in for the first time.