Return the requested image size in get_the_post_format_image()

props kovshenin. fixes #24188.

git-svn-id: https://core.svn.wordpress.org/trunk@24240 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Improve regular expressions by using a backreference to match right quote of quote pair when matching attributes.

props kovshenin. see #24225.

git-svn-id: https://core.svn.wordpress.org/trunk@24241 1a063a9b-81f0-0310-95a4-ce76da25c4cd