If you have an iPad with iOS 5 or later you can easily organize your photos on the tablet by creating photo albums. Once you have created an album you can then rearrange the order of the photos.
How to create a photo album on an iPad
You can go back to the album and edit it by adding, removing and rearranging photos in the album.
To rearrange photos in the album just touch the arrow icon in the top right corner. Then hold your finger on a photo and drag it where you want it. You can also select a photo(s) to remove it or copy it. If you tap on copy, you can then go to another app, like Mail for instance and paste the photo(s).
You can even create several albums then rearrange the order of the albums dragging them where you want.
Here’s a quick video showing how to create a photo album and arrange the photos in it.