Hello,
You could use the RID as a common identifier between ARTIQ and the computers controlling the cameras, since each experiment submitted to the ARTIQ master gets a unique RID, and it is available from the experiment through self.scheduler.rid. For example, the ARTIQ experiment could send the RID to the camera controller, and the camera computer could save its images in a specific directory.
For smaller data that can reasonably be represented as ARTIQ datasets, another possibility is to return the data to the ARTIQ experiment and store it with set_dataset().
Regarding the result path: the master stores results under:
results/<date>/<hour>/<RID>-<experiment>.h5
You can refer to the manual: