I personally couldn't care what people spend.
That said, if people want to post pictures online with presents stacked to the ceiling whilst some people can't afford any presents at all, then they open themselves to comments both good and bad.
Let's face it, if people didn't brag in the first place then others wouldn't know and therefore wouldn't grumble/bad mouth
Spend what you want, but if you don't want your feelings hurt to post online making yourself open to potential abuse