One of the little support you have in mcmod.info is providing the logo.
Other nice features in the future would be screenshots and update link. These are current unimplemented though.
Look here for more information https://github.com/MinecraftForge/FML/wiki/FML-mod-information-file
Max size is 200 x 65 px
apparently mcmod.info can not be seen indev
€: fixed with #1406
Would look like this
If you manually copy the mcmod.info into the output directory, it will load them also for indev.
apparently logo for core mods is not a thing
Closes #1404: Added logo to AE2