Hi there,
Unfortunately, Astrometry.net doesn't work on Hubble Space Telescope images -- they're too small (in angle size on the sky)! Sorry for the trouble and frustration -- that really should be advertised better...
For what it's worth, I see one of your images in a NASA/Hubble tweet,
where I see it labelled NGC 3489.
You can then go over to the sky viewer and search for that galaxy, eg,
The second one is the cluster Abell 665:
As you can see, most of these stars and galaxies don't have common names. All the elliptical orangey things will be galaxies. The bluish dots with diffraction spikes coming off them will be stars in our own Milky Way galaxy.
Hope that helps!
cheers,
dustin