I’ve had multiple reports of images appearing twice when copy/pasted into the composer window. Both of the reports are in Chrome on Windows (both v7 and v10).
I’ve not been able to reproduce this myself.
In the most recent report, the resulting raw markup is this:
![image|660x371](upload://tfHoTOzeP1SEsUQYS0AIhaIyb94.jpg)![Satellite image of Storm Caroline](https://ichef-1.bbci.co.uk/news/660/cpsprodpb/506E/production/_99109502_carolinefromspace.jpg)