QGIS atlas Picture INPUT APP

I am trying to set up a layout with the atlas-function in QGIS. I am using also the INPUT-mobile App. With the app it is possible to take pictures. I want these pictures to be displayed using the atlas-function.
For INPUT to do make the fotos work, you have to set up the Widget type = Attachment. Also one has to use relative paths. In Integrated Document Viewer section the type is set to Image.

Now when I take a pic INPUT automatically writes in the attribute table and it looks like this

To use the atlas function i have already discovered, that i can select the fotos from the attribute table. However, since there is not a complete path, it does not display the foto correctly. Now I am looking for a solution to fix this.

I thought the best way would be to store the atlas shape file in the same folder with the pictures and then create a path from the file directory somehow combining the information with the Foto file name. How can I create this path or do you have a better, more convenient idea?