can't get nextgen gallery to work – reinstall doesn't work

i’ve had a problem with my nextgen gallery and had to reinstall. apparently it became corrupt after i tried using themes and captions (as shown on the plugin website). so i just wanted to go back to the beginning and reinstall it all.

i uninstalled the plugin from the dashboard.
i then went into my ftp and deleted the folders associated with next gen

wp-content/plugens/nextgen-gallery was deleted

and

wp-content/gallery was deleted

when i’ve reinstalled, and reuploaded the images all i get is the box and name of the image but not the image itself.

my website is: https://lizartlizard.fortuin.info/?page_id=5