Because Ubuntu 7.10 repositories don't have the latest version of ImageMagick, stopping you install the latest RMagick Ruby Gem; here's a guide to help you build it from source.

What had Gone Before

Before all this, I had installed the old version of ImageMagick by,

sudo apt-get install imagemagick
sudo apt-get install libmagick9-dev

So as you know before you start.

Remove ImageMagick

First off you're gonna have to remove your old copy of ImageMagick...

sudo apt-get remove imagemagick

Building & Installing ImageMagick 6.3.8

Now we're going to get the latest source files for ImageMagick and configure them correctly.

wget ftp://ftp.imagemagick.org/pub/ImageMagick/ImageMagick-6.3.8-11.tar.gz
tar xvvzf ImageMagick-6.3.8-11.tar.gz
cd ImageMagick-6.3.8-11

Now we're in the source directory, G

./configure --prefix=/usr

Excellent, let's build...

sudo make

This will take a while, you may get a few warning pop up but hopefully no show-stoppers; afterwards lets install...

sudo make install

Rmagick Gem

And finally the latest RMagick Gem..

sudo gem install rmagick

If this still fails, you can install the old gem with..

sudo gem install rmagick -v=1.15.12

But fingers crossed let hope the new one works

Did it work?

Yes it all installed, and I've now got the RMagick 2.2.2 gem running on Ubuntu 7.10

So, What does it support?

Simple to find out, run the command below to see what version of ImageMagick you've got and what it can support.

identify -list format