I'm using Media.module 7.x-2.0-unstable7
Adding an image via the "add media" button lets my browse for an image and the select a display format.
"default" adds a small image icon and the filename linked to the actual file
"teaser" adds the image at 220px width
"preview" adds the image as a 180px x 180px square
None of these is any use if I want to display an image at its original size which might be 800px x 600px.
Am I missing something?