List of images with checkbox (user registration) This is what I would like to do:

When a user registers on the website they have to give in if some options like for example if they are politically engaged, professionally engaged, an expert, ... .

I also want a field that contains 3 images. And based on the chosen options of the user I would like to select 1,2 or 3 of them. So the user can contain image 1 &amp; 2 or ... .

So I was thinking of 3 images with 3 checkboxes and cross the checkboxes next to the images (programmatically). But is this a good way to do this? And if yes, how can I implement this?
You can do that by the following. 

Go to Configuration » People » Account settings

Add a Field type : List (text) and WIDGET: Check boxes/radio buttons

In Allowed values list  textarea add key|&lt;img src ='/your/path/to/image' /&gt; 

Enter one &lt;img&gt; per line and set Number of values as Unlimited (to appear as checkboxes)

That's it. I tested it and working fine.

Add key whatever you want.You may have to make minor CSS changes in order to align checkbox and image.

Hope this helps.