Icons in history tell you the status of the shared image.
The image is being uploaded to the Zello server.
The image was successfully uploaded to the Zello server but the recipient has not been notified.
Recipient was notified about the image and is downloading it at the moment. If the recipient is offline, the image will be sent when he signs in.
Recipient has successfully downloaded the image. If the recipient is a channel, the channel and all users who are online at that time will be notified about it.
Questions? Email firstname.lastname@example.org.