Polaroize - a service that adds slanted shadow borders to images.

Everyone can directly check the specific effect: http://hiphotos.baidu.com/comicspace/pic/item/76bfb535316d6b8ea71e127a.jpg

It is such a simple service, but I think it is still very practical. When posting images, it may come in handy. Although this is a Japanese service, language will not be a barrier. After entering the service page, you just need to click browse, select the image, and then upload it. After a while, the image with this effect will be automatically generated.