Give me a brief summary on sharing photos.
What are Challenges?
Why aren't my photos appearing on the site? Why can't I post comments?
Why are there limits on the number of photos I can upload?
In what ways are uploaded photos altered?
To whom can I send private messages?
Are there restrictions on what I can link to in the 'off-site link' field?
What are hashtags? How does tagging work?
Why am I able to upload some - but not all - of the pictures I take with my mobile phone?
What happens when I delete a photo?
What can I do if my images are on Photo Friday without my permission?