ICA-AtoM and AtoM
First, I believe that the sfColumbiaPlugin was an old ICA-AtoM 1.x theme. If you are still using ICA-AtoM 1.x, we strongly recommend that you upgrade to the latest version of AtoM - currently version 2.6.4. See:
As you may know, ICA-AtoM versions 1.x are no longer being developed and maintained. In 2013, we added a new search index, updated the user interface, rewrote all the documentation, and rebranded the application as just "AtoM" with the 2.0 release. Since that time, AtoM has received many security patches, dependency upgrades, new features, performance and scalability enhancements, and more.
The team developing AtoM 2.x is the same as ICA-AtoM 1.x, much of the original code is still the same, and it is released under the same open source license. You can upgrade directly from ICA-AtoM versions to the latest AtoM 2.6 version. See:
If you are just using a GIF for this banner, then you probably don't need any development at all. Add the GIF to your server, then link it by editing the related Static page.
We do not have documentation for ICA-AtoM custom theme plugins, but much of the basic logic is still the same in AtoM, since both still use Symfony. I am attaching a PDF that outlines how custom theme plugins are typically organized, configured, and installed, which may help you.
Keep in mind that the slides are from 2018 (i.e. release 2.5) so some things may be different in older or newer versions of AtoM.