Refresh an Inserted Picture?

[BJ]

I've got a layered visio document. The background layer
is a large JPEG that I scaled (using Visio) to fit on a
letter page. If/when the JPG image is changed (using
another program)...and I want to update my Visio
document...how can I go about this?

Is there a 'Refresh Picture' option? Can it
automatically scale/format as done during the
original 'Insert Picture' step?

Is there any way to batch process a bunch of such changes
to multiple Visio documents?

thanks