ATPhoto is included with the PloneMultimedia package along with ATAudio and ATVideo.
ATPhoto contains two main parts:

ATPhoto which is the object containing your photo.

ATPhotoAlbum which is a folder containing all your photos.

Note: there is another standalone product for Plone called ATPhotoAlbum. That is a completely separate product which must be removed from your Zope products directory if you wish to use ATPhoto. This is because there is a name conflict: both use the name ATPhotoAlbum.

Let's take a closer look at the features of each object:

ATPhoto

Flickr

Flickr has become a very popular service for hosting photos and building communities. Plone can display photos from Flickr using RSS 2.0 feeds, and even provide a mechanism to submit photos to Flickr using the Flickr API.

This API allows the export of an ATPhoto directly to your Flickr account. Just authenticate from Plone, define your tags, description and the title of the photo on Flickr.

EXIF

Most of today's cameras set tags inside a photo (e.g Orientation, date of shooting, flash usage, aperture...). ATPhoto parse them to use them for sorting and object tagging.

IPTC

More organizational tags can be embedded inside a photo (e.g Owner, Copyright, Licence...). ATPhoto can parse them. Many image editing/management software tools such as Photoshop use IPTC.

Sizes

Different sizes can be defined (e.g thumbnails, icons...) and displayed.

Export

Export the photo to different sizes and different formats (jpg, big, bmp, png, tiff, pcx, ppn). Also provides the ability to zip the newly exported photo.

Transforms

Apply different transformations on the photo: rotate, flip.
Autorotate: Will look inside the EXIF informations to know how was taken your photo and will apply the corresponding rotation.

ATPhotoAlbum

Slideshow

If you want to browse the album without having to click on the next button every two seconds, a slideshow will do it for you.
You can use different nice transitions in the slideshow (cross fade, cross wipe), the time delay between the photos and the size to use.

Sorting

ATPhotoAlbum will enable quick sorting of your photos. Either by id or by the date and time embedded in the EXIF tag (so that your photos will be sorted as you shot them).

Flickr export and import

Export the entire album of photos to your Flickr account. Just define the tags that will be set on every exported photo.

Import a Flickr sets into an ATPhotoAlbum folder.

Zip export and import

Export (recursively or not) all the photos inside your album to a zip file with a defined size and format for each photo in the album.

If you don't want to import each photo, one by one, you can zip them into a ZIP, tar, gz or bz2 file and post it to ATPhotoAlbum and it will
extract them in the album.

Batch import

ATPhotoAlbum can integrate with the PloneJUpload product (if you installed it) to import a batch of photos.

Batch size

Quickly define how many photos per ATPhotoAlbum page you want to display.

Symbolic photo

Choose the photo which should represent the album so that you can build a nice hierarchy of albums.

Portlet

ATPhoto comes with a simple portlet to show your last imported photos.