Is it possible to delete old photo uploads to free up my storage allowance?

Hi there, is it possible to delete old photo uploads to free up storage space?

Yes, but it's required to delete the submission where it was sent on, unfortunately, it's not possible to delete the file only. 

Here is a guide that will help you deleting the submissions on your form: https://www.jotform.com/help/377-How-to-Delete-Form-Submission-Data 

I hope this helps.