As far as size and dimensions are concerned; if you roll your mouse over the blank media placeholder on any screen, it will display the best dimensions to view the media. Here is a reference to use.
- 1 static media area: Use 900px wide & 515px in height
- 1 static media and text displayed horizontally: Use 900px wide and 360px in height
- 1 static media and text side by side: Use 448px wide and 336px in height