2014年5月16日 — In WeChat's “Discover” tab, head to the Sticker Shop. From there, click on the settings cog, and near the bottom you'll see the “Custom” option.
If you want to add the existing sticker to the new GIF you are making, you can directly press on the sticker and hold (A1) to activate the menu options, and ...
All you need is a phone that doesn't have a potato for a camera, access to an app store loaded with GIF converter options, and of course, a WeChat account.