Discussions is ill-suited to displaying code snippets for you, but I can link you to some examples & try to walk you through it.
First you’d have to have enough images; Cullen already has one, it’s called “Cullen Profile 2a.png” & it is located at this URL: dragonage.wikia.com/wiki/File:Cullen_Profile_2a.png
For sake of example let’s say you already have the other two images.
Now, Cullen’s actual page, you will see the image I’ve uploaded below. To get there, I recommend you get on a computer & go to dragonage.wikia.com/wiki/Cullen_Rutherford?action=edit&useeditor=source or you can just go to the actual page & press “edit”. Just remember to go to dragonage.wikia.com/wiki/Special:Preferences#mw-prefsection-editing switch to source editor, & then hit save first if you use this second method. That will ensure that your account uses source editor, which you’ll need for this. We are almost done now.
This last part may be tricky, so I’ll post that part in another reply because you’ll need to see an image example. But for now, see the image below; see the “image” parameter in the code? That’s what we will change.