The image you see here is less than 25% of the high-resolution original. Take a look at the stunning detail in the raw version here. Hubble's high-tech camera, paired with 28 hours of exposure time, made it possible to observe these faint details.
Hubble has also captured the outer spiral arms of NGC 4911, along with thousands of other galaxies of varying sizes. The Coma Cluster is home to almost 1,000 galaxies, making it one of the densest collections of galaxies in the nearby universe.
You can read up on this image here on the CosmicLog.