Do i need to spray seal or laminate a picture printed on self adhesive gloss polypropylene?
The Northeast Document Conservation Center provides a number of suggestions for preserving photographs. Neither spray sealant nor lamination are listed: http://www.nedcc.org/resources/leaflets/5Photographs/03CareOfPhotos.phpHowever, you could contact them to make sure.
you should seal anything you want permanent.
You need to laminate the picture that has been printed on a self adhesive gloss polypropylene. This is because, the lamination will provide a long lasting display of the picture and also ensure it's protected.