Spray Mount is glue in a spray can. This is so the glue can be applied thinly and evenly. Often used for mounting artwork. Easily available at bookshops and art shops. Normally known as 'spray adhesive'.
actually there's a frames shop that also have mounting services in Holland V. Quality is not bad and I use them for my projects. Can't remember the name but it's near Coffee Club. Can check it out. It's $4.50 per piece IIRC.