This one looks like a piece of jade to me with these colors. The colors are, of course, representative or "false" color, depending on how you want to word that. As an example, here is <a href="http://www.spacetelescope.org/images/potw1327a/" rel="nofollow">another rendition</a> of this nebula using almost the same data. For this, the bluer patches indicate slightly stronger OIII emissions while the greener ones are slightly stronger in H-alpha. There are tiny little red things to the left and right of the nebula glowing in NII which look something like slightly smudged stars. I presume they are tiny FLIERS.

Red: hst_11956_04_wfpc2_f658n_wf_sci Green: hst_11956_04_wfpc2_f656n_wf_sci Blue: hst_11956_04_wfpc2_f502n_wf_sci