why the colors?
why do galaxies like my first one change colors so abruptly? can anyone help me?
That image (agz0000qp1) is at the edge of the camera survey line. The various camera filters have slightly different alignments so you often see that effect here where filter coverage is thus incomplete. View using skyserver and zoom right out, you'll see the effect more clearly.
The other colours are also photographic effects caused e.g. by over-saturation of bright objects e.g. foreground stars, or speckle caused by enhancement of very low-light images.