I produce email marketing using fully tested code. In nerd speak that means inline CSS styled HTML text, tables and images. I keep costs low and I can help with ideas and copywriting where needed.
The slideshow is showing JPEGs, this is because people on the internet have a nasty habit of stealing images and code. If you want to see my HTML source code, get in touch with a genuine enquiry and I'll send you a link.
After designing, I test the HTML code via emailonacid.com and re-code to either fix or modify in order to avoid the major problems which different email clients will show. The common problems in HTML email design are due to different standards (of how the HTML code is interpreted) being adopted by different email clients, the majority of problems are from Outlook 2007 and Outlook 2010, designing specifically to appear correctly in these email clients can often mean design compromises, most specifically because extra 'gaps' will often appear between our 'content boxes' in these two email clients, meaning sometimes an image which should butt up tight against another image, has a gap between it. The ideal is to design with this in mind from the outset, or at least expect it to happen. Sometimes a small compromise can save a lot of money.