Include name of library and the location in the title.
Only submit static images.
- Videos, collections, interactive images/websites, and articles are not allowed.
- Do not submit a shortened link using a URL shortener like tinyurl.
Make sure your image is hosted by an approved host.
- Original source is allowed and preferred over the approved hosts. If your submission is not on the list of approved hosts, but it is an original source, please use the tag [OS] so your submission is not removed in error. If your image is rehosted from another approved host it will be removed.
- If you took the photo yourself, you can signify this by using the tag [OC] (original content) and after 24 hours you will be given special flair. If you don't receive flair after a few days feel free to message the mods.
Regarding reposts: it is not a repost unless it was posted to /r/LibraryPorn less than three months ago, or if it's already in the top 100 of all time.
If you have any questions check out the FAQ.

Banner image: The British Museum Reading Room (source)