Where have you heard that NASA is hiding pictures? Do you mean from the spacecraft or from the ground? Can you think of any reasonable explanation for why they would such a thing? I've seen dozens of images of this comet, from NASA and non-NASA sources. They're not doing a very good job of hiding them, if that's what they wanted to do.

CJSF

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Two years ago moved from my town
I was looking up past the city lights
But the city lights got in my way

See the constellation ride across the sky
No cigar, no lady on his arm
Just a guy made of dots and lines

-from "See The Constellation"
by They Might Be Giants