If you want to move an image to the start of a section in Visual Editor the logical course of action is to drag it to before the first character of the first word of the section.
A user of Firefox 21 reports this does not work at all, in my testing in Firefox 22 it appears to work only occasionally.
The counter-intuitive dragging the image to after the last character of the section title does work.
Version: unspecified
Severity: enhancement
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=54756
https://bugzilla.wikimedia.org/show_bug.cgi?id=65883