That inconsistency just shows that they are willing to bend the rules and history of the show to suit the jokes. It's happened before and I'm afraid it's going to keep happening.
This episode was a big letdown for me, there's absolutely no real plot progression and though the whole bit about Barney always looking suave on pictures was funny, it was also completely unnecessary and too much of a fantastical element in the show. I hope the creators are thinking about wrapping the plot up and ending the show on a good note, instead of dragging it out and going downhill.