A red blood cell has a diameter of ~8e-6m. Pick up a mechanical pencil sitting around you with a .5mm lead in it. Study the tip of that pencil and imagine 60 little red platelets lined up in a row fitting across its width. Now pick up one of those little red blood cells and stick it to a window. Then get in your car and drive 8e-6m/1e-10 or 86km away and look back across the (flat, obviously) Earth to that window. As Triangulum rises over the horizon on the other side of our window, that little red blood cell would fully eclipse our remote twin of VY Canis Majoris.
I don't know if I'm seeing individual stars in that zoomable image, but if I am I don't understand how we make optics that good. (Caveat, Hubble's resolution is rated at ~2.4e-7 radians, so it's likely that those blobs aren't stars, or my math is off somewhere.)
This is no more mysterious than the fact that you can see individual (nearby, bright) stars with your naked eye when you go outside at night. The angular resolving power of your eyes (or of small telescopes) compared to the angular diameters of even nearby stars is terrible; nonetheless, you can still see them.
The key thing to understand is that objects which are too small to resolve will be blurred by the telescope/lens/eye (plus atmospheric turbulence if you're not in space) into a point spread function [https://en.wikipedia.org/wiki/Point_spread_function]. The light from each star is thus spread out over multiple pixels in a pattern which is basically the same for all the stars, varying only in total brightness and thus detectability; for really bright stars, the light in this pattern can be traced out over a significant fraction of the entire image. This includes features like the diffraction spikes; we don't see these for stars in M33 only because they're too faint to register.
I'm imagining this being similar to how adding the right kind of noise and oversampling can tease out smaller signals than one might think possible in a noise free sampling system.
Am I off base here?
"Despite the mass and very large size, VY CMa has an average density of 5.33 to 8.38 mg/m3 (0.00000533 to 0.00000838 kg/m3), it is over 100,000 times less dense than Earth's atmosphere at sea level (1.2 kg/m3). " 
Often these huge but low density objects are incorrectly rendered like our Sun with a "hard" surface. I think it's a pity because they are even weirder and more fascinating objects than that.
How many pixels would you expect the image of the star to be? It can't be less than 1. You'd still see the individual star even though it is a lot smaller than 1 pixel. Imperfect optics mean it will likely appear larger than 1 pixel.
The fact that individual stars can be seen doesn't necessarily mean the telescope has a resolution equal to the angular size of this star. A point source will be apparent even if it isn't resolved. Otherwise we could never see stars with our naked eye.
Only addresses visible stars, which are all in our Galaxy. The thing is Andromeda actually covers more of the night sky than the moon, so I kinda wonder if an instrument could resolve individual stars. I don't know a whole lot about that other than Airy discs, which would suggest no, stars are too close to each other in angular terms.
Under the simplifying assumptions that the image is square and encompasses the exact galaxy width, that's about 22 trillion km (or ~11,000 VY Canis Majoris) per pixel. So I guess we're not seeing individual stars (edit: in the target galaxy) - or my math is also off somewhere.
Either that or all those stars are uuuuuge
Horizons on earth start at maybe 25 or 30 miles away.
Cars are about 10 feet across.
But you’re saying an 8 (maybe 6) micrometer erythrocyte, less than 10 feet away (on a car window), can eclipse a half a millimeter graphite pencil lead at a distance of 86Km (53 miles)?
Also, a meter is a million micrometers. A millimeter is a thousand micrometers. You would need 100 copies of a 10 micrometer object, to span a millimeter. Fifty, to span half.
Are you saying VY Canis Majoris is the erythrocyte to Triangulum’s pencil lead? As it eclipses said object at 53 miles?
Or are you saying the erythrocyte is fixed onto a house window, and an erythrocyte can occlude the direct observation of an actual star in the sky (the biggest one we know of), even at 53 miles, which is over, beyond and even twice past any terrestrial horizon, and would need to be on a window in a skyscraper taller than anything ever built?
EDIT: Sorry, the Burj Kalifa is 2,700 feet tall, so its spire would peek over the horizon, even at distances up to around 60 miles. So, I need to update my mental trivia model. We actually have built something that big, but it only happened about ten years ago.
Yes. Also, I'm pretty sure your objections here are handled by "(flat, obviously)". The point is to make an analogy to sizes and distances on a human scale, not to make a point about the geometry of Earth.
Anybody know what the story is with the lens flare on some of the bigger/brighter objects? For some reason I expected that a Hubble image would be beyond such things.
EDIT - for Hubble specifically, here’s an exploded view: https://www.spacetelescope.org/images/exploded_view1/
The spikes are caused by the arms holding the secondary mirror.
So I visited Scale of the Universe  to try to get a grip on things. Wonderful site (and music!), but I think it had the opposite of the desired effect. I am now completely numb to any notion of trailing zeros.
Suppose you were on an earthlike planet orbiting some star near the center of it. Do you suppose the "night sky" would be about as bright as day due to the number of stars?
Apologies in advance to the real scientists here for my naivete, however: As we know there's billions of galaxies too - it makes me feel like everything is just a big Mandelbrot set. We've picked galaxies on the top end, and atoms on the other, but is that really where it ends, or is it just the edges of our ability to perceive?
Going up, galaxies make up groups which combine into superclusters that form the cosmic web of the observable universe.
So for all intents and purposes, we can essentially say the universe and the various scales are infinite because it may as well be for humans.
I have seen that bright star forming region in telescopes and it always blows me away to think it is a nebula in another galaxy.
The closest thing we have to a large star forming region is the Orion nebula but the one there is so big that if it were where the Orion nebula is, our solar system would be inside it.
I sure hope interstellar travel is something that intelligent civilizations do, our galaxy is full of them, and the Fermi paradox is because Earth is in some sort of nature preserve situation, not because of a great filter we are yet to encounter.
 http://hubblesite.org/image/351/news_release/1995-44 -- "The color image is constructed from three separate images taken in the light of emission from different types of atoms. Red shows emission from singly-ionized sulfur atoms. Green shows emission from hydrogen. Blue shows light emitted by doubly- ionized oxygen atoms."