I would probably embed the images, since that is becoming the standard for most email newsletters these days. It used to be that linking to them on a Web site was the standard, but as ISPs have steadily increased the maximum size of a message, that's changed. I notice that some of the technical newsletters have switched in the last year or two to embedded images; in fact, now that I think about it, I don't think I'm currently getting any newsletters with remote-hosted images.
