On the page that has the upload behavior, look in the bindings panel, expand the WA Uploaded files (Fiel Field Name) group, there is a binding called Server File Name that will be populated with the name of the uplaoded file.
I assume this is a registrastion form? in the insert record behavior, bind the image column ot the server file name variable to store the image in the database, now the authenticate user behavior should be able to pick it up when the user registers.