Lightbox gallery displays many times the profile picture and additional ones

STEPS TO REPRODUCE

1. Login as Admin
2. Go to Administer Wiki > Look & Feel > Lightbox and enable it
3. Create a new user (e.g. U1)
4. Login with this user
5. Go to user profile and set a picture
6. Hover over the profile picture and click 'Image gallery' button
7. Click 'Next image' buttons (right/left)
8. Go to a page and perform an action (e.g. add a comment)
9. Go back to user profile, hover over the profile picture and click on 'Image gallery'

EXPECTED RESULTS

The lightbox gallery shows one picture: the profile one.

ACTUAL RESULTS

After first uploading the profile picture, the lightbox gallery displays it 4 times and 2 additional "Loading..." pictures.

Also, it seems that after every action performed by the user (edit, comment, etc), the number of times the profile picture is displayed increases, please see screenshot.