Rexl asks:

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i hear these photos are black and white and then colored by artists at nasa or somewhere, so the colors are someone's imagination. right?
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No.

The large showpiece Hubble Telescope images are composites of multiple exposures (each one often taking many hours). They are all digital, meaning that the actual light gathered through the telescope lens is creating a bunch of zeros and ones in computer file, rather than creating a bunch of darkened silver iodide molecules (photographic plates). Color film itself is basically three chemical gels which are sensitive to three colors (magenta, cyan, yellow) that are then blended to reproduce something approaching what our eyes appear to see.

It's really complicated. Google Hubble Space Telescope and image details to learn more.