A simple concrete5 add-on which allows you to show a picture and some text when you hover it.
Install it by running this command in the packages directory of your concrete5 site:
git clone https://github.com/Remo/concrete5-cover-picture.git cover_picture
You can also download it by following this link https://github.com/Remo/concrete5-cover-picture/archive/master.zip, but please note that you'll have to rename the first directory in the ZIP to "cover_picture".
Sponsored by https://www.madeforspace.com/, Michele Locati has created a version of this block for 5.7, https://github.com/mlocati/concrete5-cover-picture-7