Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
Img.vision - Image hosting & video hosting for eCommerce sellers
Flickr - image and video hosting website
UploadHouse - Thumbnail and resize your photos and images
imgbox - Imgbox is a free image hosting service.
ImageVenue - ImageVenue is a great online hosting service that allows uploading pictures for showing creative works with a simple-to-use technique.