Photo names .jpg and meta:instanceID edition

I'm French so my English is really bad ... I hope I do not make too many mistakes!

I tried for several days to automatically change the names of photos taken in the forms but I gave up. Instead, I'm trying to just get the name of the image in the excel file (.jpg, not the url ...) to match the photo uploaded by ODK Briefase. Do you have an idea ? It does not matter if the name of the image appears in the form in ODK Collect .... I will turn it as a summary of the attachments at worst ...

Also, I would like to modify the meta: instanceID that begins with "uuid" and name it from the variables obtained in the form (the date and number of the measure). This will be to properly name the folders containing the photos after they are uploaded into the ODK Briefcase.

My way : Excel => xls to xml => ODK Aggregate => ODK Collect => ODK Aggregate => csv and ODK Briefcase (pictures)

Thank you very much for your advice !