Would I need to purchase anything else to install it as a replacement to my current HDD? I noticed that in some of the pictures the case is missing, exposing the internal components. Would I need something to cover that or have they just removed the cover to show it?
I have a SATA cable and a power supply that I should be able to use from my previous HDD as far as I know.
The picture doesn't represent how it ships (speaking of the opened HDD case showing the platters). It's unsafe to the HDD expose the platters to dust! Anyway, you should have everything else you need: all you need is the drive itself, cables and whatever mounting screws (the latter stuff pulled off the old drive)
the photo is how bulk drives look like. all you need is two drive rails or four drive screws to mount the drive in a case. just be care full to use the right length screws so you dont drill into the pcb.