Historically, users were able to right-click > 'copy image' and paste a GIF into a teams chat. In the last few weeks, users are reporting that this does not seems to be working in conversations. GIF plugin has been enabled in conversations for the organization, however, not enabled for teams channels. When using the GIF button in conversations, GIFs are able to be posted, but the copy/pasting of clipboard copied images no longer result in GIFs pasting into the chat. Doing so via the web client indicates that the GIF will post until the message is sent and results in the following image: Result of pasted GIF
Performing the same steps in a teams team, does, however, allow the clipboard contents to paste and display.