The best guidelines I have found for crafting HTML emails supported by all major clients: Campaign Monitor Email Design Guidelines (scroll down for their discu

The best guidelines I have found for crafting HTML emails supported by all major clients: Campaign Monitor Email Design Guidelines (scroll down for their discussion on images) http://www.campaignmonitor.com/resources/will-it-work/guidelines/ http://www.campaignmonitor.com/resources/will-it-work/guidel... Image Blocking: http://www.campaignmonitor.com/resources/will-it-work/image-blocking/ http://www.campaignmonitor.com/resources/will-it-work/image-... CSS Support: http://www.campaignmonitor.com/css/ http://www.campaignmonitor.com/css/