I have some problem with Thunderbird and IE that my full width image hides some of the content text behind the image. Outlook and Firefox are ok though.
What is the proper way to get inline image push the content and topic down, under it?
It sounds like you don't want the image to be inline, you want it to be a block level element? You could just add CSS to your template to ensure that images are set to display:block perhaps.
How do I used a jpeg image so that it does not appear as an attachment in my emails?