I'm cutting from within Sigil and pasting to another spot in Sigil. Weird.
So, one awesome thing-your insert image works perfectly for me. I am slowly adding some illustrations/diagrams into an ePub that had been converted from HTML (and all graphics were stripped). I tried a couple, re-saved as ePub, then opened in Stanza Desktop. Unfortunately, Stanza Desktop does NOT show images, but when you transfer the file to the iPhone, the images show up correctly.
What is the advantage right now in saving in Sigil format, instead of always saving back to ePub?