Thank you for this! Here's another (thx to @jrhughes):
After using blockquote, create a space with ***
For two photos side by side (thx to @pegasusphysics):

HOWEVER,
I'm having trouble with text appearing between the two photos, and forcing a line break ( --- or *** ) doesn't fix it. I'll have to try your
or

and see if that works.
Also, using the --- underline command will usually BUT NOT ALWAYS cause the text above the line to go bold and sans serif.
I have more formatting glitches than I even know how to explain, much less how to get help fixing!
Thanks for this, @blackliberal.
----And now I can't get the formatting for side-by-side photos to show up in a comment box!