In an openSUSE 11.1 I download, compile and install ImageMagick via:

wget ftp://.../pub/graphics/ImageMagick/ImageMagick-6.7.7-0.zip
unzip ImageMagick-6.7.7-0.zip
cd ImageMagick-6.7.7-0
./configure --prefix=/usr/local/ImageMagick
make
make install

Everything works nicelly until I discover that JPG is not supported:

identify -list format | grep -i jpg

[nothing related to JPG returned]

So I reconfigure and recompile using:

./configure --prefix=/usr/local/ImageMagick --with-jpeg=yes --with-jp2=yes
make
make install

But that changes nothing.

I end up uninstalling:

make uninstall

and installing via zypper:

zypper install ImageMagick

This installed version 6.4.3 and now it does support JPG:

identify -list format | grep -i jpg
JPG* JPEG      rw-   Joint Photographic Experts Group JFIF format

Any idea on what is going on here? What is a possible reason that this capability of ImageMagick was not there when compiled from source but was there when installed from rpm?

Note that I don't necessarily care a lot about ImageMagick (since it now works), but generally about his kind of behaviour, becase in one way or another I've seen this happen in other ocasions as well.