The legacy version of Rapid Photo Downloader is 0.4.11. The instructions here refer to that legacy version. The instructions on the most recent version are found here.
Rapid Photo Downloader 0.4.11 runs on all versions from Wily Werewolf (15.10) to Trusty Tahr (14.04 LTS). Older versions of Ubuntu are not supported. It also runs on Ubuntu derivatives like Linux Mint, Kubuntu, Lubuntu and Xubuntu.
Installation under Ubuntu is an easy two-step process. First, setup the Personal Package Archive (PPA) used by Rapid Photo Downloader. Second, install Rapid Photo Downloader in the usual way — for example, through apt-get or the software center.
PPAs work like normal Ubuntu archives. Whenever Rapid Photo Downloader is updated, Ubuntu will prompt you to install it. The PPA for Rapid Photo Downloader is located at https://launchpad.net/~dlynch3/+archive/ppa.
If you don't know what it means to add a repository, or how to do it, then read more.
You can use Ubuntu's easy to use graphical tools to add the following to your Software Sources:
However, it is probably more easily done from the command line, where you can install the program in three easy steps:
All users should then run the following steps:
sudo apt-get install rapid-photo-downloader
To install a testing version, you need to add the Rapid Photo Downloader Testing PPA:
sudo apt-get update
sudo apt-get install rapid-photo-downloader
The name of the package to install is rapid-photo-downloader.
If you don't know how to install new packages, Ubuntu's official documentation contains instructions on how to do this.

If you like this software, please consider making a contribution. Thank you!