I've created photo galleries on my blog. I used tables and it was easy to embed pics from Picasa. I did some complicated thing to embed pics from Google+ not too long ago but I cannot figure it out again. So, how can I embed a single photo from Google+?
Depending on how streamlined you want this process, it seems to be fairly trivial to get the public URL of individual photos using the tools in your browser.
When you are viewing the photo (either full screen or just the thumbnail) on Google+ you can select "Copy image URL" (Chrome) or "Copy Image Location" (Firefox) from the right-mouse/context menu. You can then use this URL on your blog/website.
All images on Google+ are publicly accessible (not even sure you can make them private?) - only hidden behind an obscure/hard to guess URL - so there are no permissions that need to be changed.