Other than small emoticons, there are also larger stickers available, which you can use in chat messages on Facebook. If you don't like the pre-installed ones, you can download more for free. To do this, open a chat dialog in the Facebook app. While you can insert the available emoticons via the plus sign to the left of the input field, there is a new smiley to access stickers to the right of the input field. The first set of stickers is already available.
The lower menu bar facilitates the access to the recently used stickers, different sticker collections as well as the purchase basket of sticker store. You can select more sticker sets here and download them free of cost via the arrow symbol. Scroll through the respective collection and click the sticker to send it in the current chat. Unlike the emoticons, the image is not inserted in the text, but separately and immediately without further confirmation. The whole thing is a rather amusing form of nudging via images. TIP On the Facebook website, the smiley is in the input field. The standard Smileys and a mini-selection of stickers are available here you can expand it as suggested via the Facebook app.