Simple bootable photo drive

[Parsa9]

I bought a portable 500 GB Mercury On-the-go drive and want to use it to store photos and other images that are taking up a lot of my main laptop drive. I have no problem dragging the files over, but would also like to have a minimal system software setup or booting and checking the main drive on the road. What's the easiest way to do this?
I don't want to clone my whole drive. I've done that on a large external using SuperDuper. I just want the minimal boot software and the rest for storage.
Should I just load from a disk, or is there an easy way to do this from my computer?

[ElDiabloConCaca]

Partition the external drive into two partitions: a small, 15GB partition for booting, and the rest for data.

Install a minimal Mac OS X installation on the 15GB partition -- you may even be able to get away with a smaller partition -- and load your favorite maintenance utilities on that partition.

[Parsa9]

My large HD is partitioned with a bootable clone, as well as other partitions I use for various storage purposes. But what is the main purpose of the smaller bootable partition? What are the advantages? For repairing the other partition?

[ElDiabloConCaca]

Are you wanting some kind of bootable partition that is significantly smaller than a regular, minimal OS X installation?

I just want the minimal boot software and the rest for storage.
Should I just load from a disk, or is there an easy way to do this from my computer?

I think the way I explained is the easiest way to accomplish this... or are you looking for something different?

[Parsa9]

No, not particularly small. I was just wondering about the advantages over have a single-partition drive.

I don't have an OS 10.5 DVD, but I have my install disks for my Macbook Pro. I suppose I can use that as long as I'm using my MBP to do it, right? I can then upgrade to the latest version.

[ElDiabloConCaca]

Yep, that should work!