Hubble Hiding Things In Photos Of Space? Options

[Tramatize]

Now i don't really believe in "aliens" but i do think that it could be possible.
But me and my friends were doing a project on space and we found photos at Hubblesite.org that had peices cut out of it.
And some were pretty big peices missing.
Now i don't know why they did it, but there has to be a reason.
What do you think about it?

One of the photos that are missing something.

click to enlarge

I posted this in News because i didn't know where else it should go, if you think it should be moved, please do so.