The almost surreal nature of this image is due to this: Nothing in this image is sunlit. According to Emily Lackdawalla’s Planetary Society blog, the lower brightest area is lit by the rings of Saturn, by way of reflection off of Saturn’s disc. The right hand side is comparatively low-lit by the moons Tethys and Dione and the left side is also low-lit by the moon Rhea. To the human eye, this scene would appear far darker than seen here and is a testament to the sensitivity of Cassini’s cameras in low-lit situations. If the sun-lit side of Enceladus presented itself here, it would be a complete white out devoid of any details.
My best guess for all the dots is that some are actually star light, while others are anomalies in the imaging process… for instance, the specks in the image that appear over the disc itself are surely noise.