When I share a Firebase Dynamic Link with social image url already set on iMessage, there are only some images which will have preview image generated. Only iMessage has this issue, as there are always preview images in other platforms like Slack, Messenger, etc. I have tried many different image format and size but still cannot figure out the reason why some images do not generate preview. I’m not sure if the problem is caused by Firebase Dynamic Link, or iMessage, or the image itself.