CleanUp.Pictures - Quickly retouch any image from a browser, for free.
Bg Eraser - Background Eraser on Mac and Windows.
Flickr - image and video hosting website
ImgCleaner - Clean up pictures and images 100% free
PicWish - Remove image background automatically with ease. You will get a transparent background in 3 seconds. Totally free!
Unsplash - Unsplash is a website with high-quality free HD images. It has a catalog of more than three hundred thousand striking images that are neatly organized with tags. Read more about Unsplash.