btw for a tiny its fairly decent but could be executed better
had to 2 part this yappathon but i wanna see you get better
then try your best to place stars randomly using add tool white brush, making sure to vary the length of hold and positioning enough that it isn't pseudo-random. for starburst regions, simply use a 51, 0, 0 or red add brush and then make it centrally mostly white ALSO make sure your cores center is always a full white, but even bigger if the galactic nucleus is active (like per-say, a seyfert)
very tiny, to upscale i reccomend first using brushes to paint a rough colour map of a galaxy, its core and arms (as well as the dust between and surrounding the arms! blend it well (will taketime to refine skill) then use 51, 51, 51 add tool to make bright areas, and a subtract tool lightish azure blue brush which works by darkening in the way dust would (also requires skill)