jdMorgan - 3:59 am on Jun 26, 2010 (gmt 0)
First: Is the "?" in "jpe?g" a typo?
Basic regular expressions. "?" is a quantifier that says "Match zero or one of the preceding character, bracketed character group, or parenthesized sub-expression." It therefore makes the "e" optional, so that subpattern matches either "jpeg" or "jpg."
Second: What is RewriteRule ^ - [L] saying? Do nothing?
"Match any requested URL-path and if the preceding RewriteConds are true, leave the URL-path unchanged and stop mod_rewrite processing here."
Third: The last 3 lines. I should replace these directories with whatever directories I have on my website?
I have no idea. Those directories first appear in code you posted, and I presume they are "common" subdirectories associated with WordPress.
I don't know what you mean by "4" above. If you are saying that changing the <Limit PUT DELETE> container to a <LimitExcept GET POST> container causes 500-Server Errors, then there's either a typo or your server is toast... The former is much more likely, especially since it looks like I double-typed the "e" in the closing "</LimitExcept>" directive above.