Image to represent a project page?

Hi All,

Here we go:

I would like to add to each project page an image, which represents this project. Those images should be tile on the front page - for easy access, this also allows me to always show the latest projects.

At the moment I am adding each picture with CSS, which is not useful in the long run.
Does anyone know if there is a way to just give each project page a 'representation image' so there is no coding involved??

Hope this made all sense. Thank you.