Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
Img Safe - Host JP1G, GIF and PNG images up to 16MB each.
Tabday - Tabday is an online image organizing and sharing application.
ImageShack - Unlimited space to host images, easy to use image uploader, albums, photo hosting, sharing, dynamic image resizing on web and mobile.
ImgBB - Upload and share your images.
imgbox - Imgbox is a free image hosting service.