You can send and receive unlimited picture messages between Fongo numbers. You can send picture messages to non-Fongo numbers, the recipient will receive a clickable link to the image that can be viewed in a browser. MMS ("Picture Messages") sent from a non-Fongo number to a Fongo number is not supported at this time and there will be no notification that someone has attempted to send you an MMS.
This is a limitation of virtual phone services in Canada. Each carrier must decide to route media to other carriers.