Here's a quick and dirty on installing the latest (version 6.5.0-0 as of this writing) ImageMagick on Ubuntu 8.04.
Start by removing any old versions previously installed via apt-get:
sudo apt-get remove imagemagick
Then update apt-get and install some supporting packages:
Use wget to grab the source from ImageMagick.org.
Once the source is downloaded, uncompress it:
tar -xzf ImageMagick.tar.gz
Now configure and make:
cd ImageMagick-6.5.0-0 ./configure sudo make sudo make install
To avoid an error such as:
Add the following line to ~/.bashrc:
export LD_LIBRARY_PATH=/usr/local/lib
Update: If you still get an error like the one above, try running ldconfig:
sudo ldconfig
You can confirm the install and available formats with:
identify -list format