This can be done with several API calls. For example, you can:
[Generate an Animated GIF](http://cloudinary.com/blog/cloud_based_animated_gif_generation) of multiple images that share the same tag
Re-upload the result Animated GIF [as a "Video"](http://cloudinary.com/documentation/video_management#upload_videos) while applying [an incoming transformation](http://cloudinary.com/documentation/upload_videos#incoming_transformations) which converts the Animated GIF to an MP4 video.
Alternatively, you can do it by having a video underlay and concatenate images on top of it with using fl_layer.