Hi,
Actually, this behavior is correct. If the paging is enabled, information about 20 images is selected from the database and html code contains only these 20 pictures. That is the reason why lightbox display only 20 pictures without possibility to continue with picture number 21.
If the paging is enabled, you tell the system to display only 20 images. Images 21-40 should be display after clicking on page number 2.
To achieve your goal you will need to create your
custom webpart, selecting all data from the database, but displaying only requested number.
Best regards,
Ivana Tomanickova