Upload image on product detail page

Hi

I am new in Shopware and I need to upload pictures as  new  attibutes to order. I successfuly create order attributes and I can see it on backend. Also I can insert values to attibutes using

 Shopware\_Modules\_Order\_SendMail\_FilterVariables event. My issue is that I cannot find anywhere how to uplaod images on frontend and get URL od file. Can anyone help me?