Hi @spizam,
There are a couple of ways you could do this depending on how you want to set things up.
Are you downloading the photos to a folder? If so, then I would recommend setting up your workflow as follows:

1. Using the Directory and File Path reader, read and filter for the images that have been downloaded already.
2. Use a ProjectWiseWSGConnector, with the "List" action to list all the files from the folder you were downloading from.
3. Then use a FeatureJoiner to join the files based on the photo name - this is assuming that the file names have not changed. I would verify that the attribute, _document_name, from the ProjectWiseWSGConnector holds the same file name as the path_filename attribute
4. Then you can use the unjoined features to feed into the next ProjectWiseWSGConnector to download the files. You can specify the attribute, _object_id, in the ProjectWise Source>Object ID parameter. Then you can continue your workflow as before.
Another way you might want to consider is to use a ProjectWiseWSGConnector with the List action and use a Tester to filter based on the creation date or update date attribute. This would be useful if you are running this on a schedule and only want to download the files created in the last day for example. After the Tester, you can then connect to the remainder of your workflow to download the photos etc.
Hope this helps give you some ideas!
- Andrea