Actually the word official don't fit here because the logo we are currently using as a symbol for bitcoin was designed by bitboy and the community now used it as bitcoin logo everywhere but it was not official from satoshi so we can say that it's the community who support the new logo and in future some more came and it's adopted by all it will be treated as the official logo.

Yeah there could be any reasons and soetimes images are hosted for particular time period over the image hosting site which may vanish them after such time period or as you said forum doesn't allow images to be visible from some particular sites but we can always see them in archived version.