Recently I ran into a problem with ImageMagick, rmagick and my Rails application. Somehow my environment was messy and it included varied versions of ImageMagick. This is what I did to solve the problem:
1. Removed all installations of ImageMagick
There was one version that was compiled and installed. I uninstalled it doing this:
# go to wherever you have your make file
cd /usr/local/ImageMagick-6.4.9-4
# run make uninstall with sudo, this rollbacks make install
sudo make uninstall
There was another version that was installed using yum. I uninstalled it doing this:
sudo yum erase ImageMagick
2. Removed all ImageMagick directories from my environment, like this:
I had to repeat the following step a couple of times with different directories:
# you must have root privileges
# this updates the filesystem database to use locate
updatedb
# this finds whatever files/directories have ImageMagick in it
locate ImageMagick
# this gets rid of the ImageMagick library (which wasn’t getting used, anyway..)
sudo rm -r /usr/local/lib/ImageMagick-6.4.9
Basically I got rid of all the unnecessary ImageMagick directories (since I had already uninstalled ImageMagick)
3. Installed libpng using yum:
sudo yum install libpng
4. Installed ImageMagick-devel using yum:
Before I did this, I tried to install rmagick’s gem. (just for the fun of it)
That didn’t work because rmagick didn’t find ImageMagick in the environment.
sudo yum install Magick-devel
5. Installed rmagick
sudo gem install rmagick
6. Restarted my application
I don’t know if this step was necessary, but I did it anyway.
That solved the “unknown format: png” error that I was getting. In days like today I love yum.
