SFW . Safe For Work: Photos that contain do NOT contain nudity.

NSFW . Not Safe For Work: Photos containing nudity.

In our effort to comply with server hosting and advertiser requirements, we require you to clearly label images that contain nudity with the NSFW tag.
Images that contain nudity but have not been tagged NSFW, will be deleted.
Frequent and repeat offenders will have their IP addresses blocked from using the service.
Please, help us provide quality hosting by complying with this new policy.
Thank you.

--The UpMyPhoto Team