The Photo Gallery content type is provided by Plugin Multimedia (installed by default in the Ametys demo application).
This type allows you to select a series of images to be presented in the form of galleries or page slideshows.
This content is made up of a number of fields of the Article content type:
It is then composed of an unlimited series of photos.
In editing mode, select an image from your hard disk (local image) or from the Resource Explorer (shared image).
For each photo, you can define an alternative text.
On each gallery item, use the buttons on the right to reorder, add or delete the file.
The rendering of the gallery depends on your graphic charter. Here are 2 examples.