very nice, that the image component in iOS thunkable is capable of showing GIF files . I use cloudinary for storing and processing of images and videos.
There are people, who say, that GIF is actually too old and mp4 or webm is much better. Will you go towards these video formats and make a component to show videos or will you stick to GIF (cloudinary can produce both)? - This is important for me to plan my app concept.
You are right, WebViewer displays an error, but on iOS 10.3 (iPhone5) after that the system player is opened and the file is played, and on iOS 11.4 the playback occurs in WebViewer without error.
I correctly understand that on your Iphone 4s, iOS 9.3.5 system player does not appear?
Try playing around with the WebViewer.allowsInlineMediaPlayback property.
Try to open my link in an external browser using the “open link” block. This way you also do not play the file?