UPLOAD IMAGE IN SHOP CART

I've made a field where customers could upload their picture or logo.

It is working as far as I could upload, see and send this logo. I could review it in the shoppingcart.
But where is the file located online: it is not stored in the database.

I should need this logo to print on shirts or whatever.

I could arrange the field to upload a logo or picture in the shoppingcart.

The picture is stored in the database. BUT when the field is not used - no logo uploaded - then the logo from the previous order is stored in the database.

Something is going wrong.
Could anybody help me out?