Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
PostImage.org - Provides free image upload and hosting integration for forums.
Flickr - image and video hosting website
Pic Time - Pic Time is a versatile utility that comes with online galleries’ exclusive service with multiple tools and features.
imgbox - Imgbox is a free image hosting service.
Stampsy - A single place to share, curate and discover visual content