Once the Bitmap+ references the image file is becoming locked and can’t be overwritten. This prevents roundtripping between the new Grasshopper Texture nodes (available in the Rhino 9 WIP) and the Bitmap+ plugin. These two working together have a big potential, so it’s a pity.
@DavidMans can this work without locking the file?
P.S.
Javid plugin has an Open Bitmap component that do not lock the file.