I couldn't insert an image (using button INSERT IMAGE)in Table-Edit mode the easy way. I was waiting and waiting but no dialog screen from where I could select the image appeared.
Eventually I had to insert the HTML code with the source of an image instead right into the cell. Then it finally worked.
I have your plugin version 1,93 and wordpress 3,4,2 and I tried on Firefox and Chrome browsers and 2 different themes TwentyEleven and Regal Theme.
Please check maybe it is a bug or something.