This will be information kept in the database. Just tick the module and click on delete.
As for the information, thats just the way module information is displayed. Many modules add detailed descriptions/installation instructions that get displayed in the Module area.
There are many uses for image manager, you can showcase products, advertising, maybe display a few images from a gallery with a direct link to the gallery itself. Or as Im using it for, enticing visitors to signup to the site using text layered over graphics.