// Well in the two photo's shown there the camera angle is totally different! //
Yes, and I expect things like lighting will also play a part in making the advertised product look better than something produced in shops.
But that's what I mean by "presenting... in a favourable light", and is at times annoying but hardly counts as deception, any more than we sometimes flatter ourselves in our own pictures with make-up, lighting, etc. Nor is the amount of filling necessarily a problem, because that might be variable and down to the staff.
But if burgers are habitually significantly (say, 30%) smaller than advertised, that surely counts as more than just a bit of artistic licence.
At the other end of the scale I'm reminded of someone's order of fish and orange -- I'll have to dig it up, but imagine a picture of beautifully-cooked, two-Michelin star-level fish, with delicious orange sauce and perfect veg, and then getting a delivery of a half-eaten orange and two fish balls that they dropped in the fryer alongside the Mars bars.