Hello,
Currently, it is impossible to load a photo into the jpegPhoto attribute via the Web Interface. In the next major version of Adaxes, we a re going to improve handling of photos in Adaxes, including the possibility to use more attributes for photos than just thumbnailPhoto.
Until the new version is available, you can update the jpegPhoto attribute using a script. For example, you can create a script that will load a photo for a user from a certain file share. Then, you can create a Custom Command that can be used in Adaxes to run the script on a particular user. If you need, we can provide you a script sample.