I recently visited a server where no matter what texture pack I used, they had managed to change the paintings to display as advertisement signs (donator rank information etc.)

This would be incredibly beneficial for use on my bungee cord servers as there is lots of information to let players know about, so instead of rows and rows of signs I could just use paintings with the information included on them.

Does anyone know how I can do this (exactly, let me know what files etc I would need to change and how to implement it) or do they know of any mod/plugin that will let me do this.

I have tried a good old Google search but cant find out how it is done, I have a rough idea on how to change the paintings in a texture pack for me, but how is it done on a server where everyone visiting is using a different texture pack, but still they all see the same pictures.

Thanks in advance for any advice given.

EllisWin