Yes, it is possible to use GIFs as thumbnails for "Made in Webflow" showcase projects. However, it's worth noting that the behavior you are experiencing, where the GIF thumbnails are not playing and instead showing the first still image frame, is a known limitation in Webflow.
Webflow currently generates thumbnails for showcase projects by taking a snapshot of the first frame of the GIF. This default behavior is intentional and aimed at optimizing performance by reducing the file size of thumbnails.
To have your GIF thumbnails play as expected, you may need to use custom code or workarounds. One approach is to replace the generated thumbnail with a separate video file that contains the full animation of the GIF. You can create a video file using software like Adobe Premiere or online converters.
Once you have the video file, you can upload it to a video hosting platform like YouTube or Vimeo. Then, you can use the embed code provided by the video hosting platform to embed the video into your project thumbnail. This will allow the GIF to play as expected.
Keep in mind that this workaround may introduce additional complexities and considerations, such as managing video hosting, load times, and compatibility across different devices and browsers. It's important to test thoroughly and ensure that the solution meets your project requirements.
Lastly, it's worth mentioning that the Webflow team is continuously improving the platform based on user feedback and requests. While I don't have access to future updates, it's possible that Webflow may enhance the thumbnail functionality in the future to support GIF playback.