How to update or Insert a picture already uploaded ?

Hi! I would like to know how to Insert or update into a Database a picture already uploaded ? I can perform a insert/update code with onclick event with text box values but How to do this with a picture ? I tried with a image value, without success…

Ideally I would like the User can click on the uploaded image to submit information including this same image in the submitted DB row ! I’am beginner in coding, so I need a concrete example to understand!

Thank you!