Mostly people speak of photo sharing (Wikipedia (en)):
Photo sharing is the publishing or transfer of a user's digital photos online. Photo-sharing websites offer services such as uploading, hosting, managing and sharing of photos (publicly or privately). This function is provided through both websites and applications that facilitate the upload and display of images. The term can also be loosely applied to the use of online photo galleries that are set up and managed by individual users, including photoblogs. Sharing means that other users can view but not necessarily download the photos, users being able to select different copyright options for their photos.