On the full featured slideshow, the visitors can enter comments to the photos.
To switch this feature on, Tick Basic settings -> General -> I -> Item 4: Enable Comments.

You can configure the behaviour like: if the user must be logged in, if an email address is required, if a smileypicker is present, avatar display, moderation, notification emails, points rewards etc... Click the See also link near the activation checkbox Ito see all the related settings.

To show the photos that have recent comments, you can activate the ComTen widget, see the sidebar.

There is also a shortcode version for displaying the most recently commented photos.
In this example 0: system wide, 12: max 12 photos:
[wppa type="thumbs" album="#comten,0,12"]

Docs by subject•Commentaires•Photos commentées récemment
Vogel (Tina)
Notes: 4.67
2 commentaires
119 vus
Berglandschap (Jaap Breetvelt)
Notes: 4.00
2 commentaires
144 vus
Zeegezicht (Jaap Breetvelt)
Notes: 4.33
1 commentaire
142 vus
Marco_Porcio_Caton_Major (wppa-admin)
Camera info

Notes: 5.00
1 commentaire
267 vus
2016 (wppa-admin)
Camera info

1 commentaire
164 vus
Owens L 02-06.jpg (wppa-admin)
1 commentaire
158 vus
HPIM2828 (Kimmy Breetvelt)
Camera info

1 commentaire
303 vus
MĂ©daille d'argent
HPIM0467.jpg (opajaap)
Views: 6046 times
Notes: 3.30
3 commentaires
6046 vus
MĂ©daille d'or
HPIM2380.JPG (opajaap)
Views: 4353 times
Notes: 3.91
2 commentaires
4353 vus
Perlhyazinthe (translator)
QuiMakroaufnahme mit Retroadapter
Camera info

1 commentaire
292 vus
MĂ©daille d'or
HPIM1531.JPG (opajaap)
Views: 7425 times
Notes: 3.53
2 commentaires
7425 vus
HPIM0566.JPG (opajaap)
Camera info
Views: 663 times
Notes: 3.83
1 commentaire
663 vus

You can see the comments when you click on the thumbnails, they link to the slideshow.

However... It is most likely that you want the given comments to be shown together with the thumbnails. To achieve this, tick Item 7: ComTen alt display and you will get this display:
[wppa type="thumbs" album="#comten,0,12"]

URL fournie invalide ou incomplète fournie

Note: This works only with thumbnail type default. You can force the use of type default using inline settings e.g.:
[wppa_set name="wppa_thumbtype" value="default"]
[wppa type="thumbs" album="#comten,0,12"]

See also In-line settings