Both an image and a feature request …
I would like to have the ability to use a current Mosaic project to add new Panels, for example the image below I would like to add a top row and a bottom row … a feature would be that you can grow columns and rows, left and wright up and down …
NGC1499-1333 by Yves, on Flickr
I have a bit of a “trick” that I did when I wanted to add to a mosaic. I went into framing mosaic wizard and selected one of my panels. I don’t recall which, I think it was one with a lot of the detail. In your picture I’d probably choose the part with the most of the California nebula. Then I rotated the framing to match my camera angle, (blue box) then expanded from there. This allowed me to add to the mosaic and prevented me from needing to rotate my camera.
You might be able to use your Astrobin for this image as well.
Side note, this is a very pretty iamge! Lot’s of dust, great color!