Copy Opaque Image
Copy image with transparency removed, from the context menu.
What is Copy Opaque Image?
Copy Opaque Image is a Firefox add-on that allows you to copy images from websites, removing their transparency and replacing it with white. This solves the problem of images turning black when copied from websites like Jupyter Notebook.
Click "Copy Opaque Image" from the context menu. The pasted image's transparent part will be replaced by white. This can workaround the problem of images turning black when copied from some websites (e.g. Jupyter Notebook).
Copy Opaque Image may not be safe to use and it requires some risky permissions. Exercise caution when installing this add-on. Review carefully before installing.
Copy Opaque Image has earned a fairly good reputation and likely can be trusted.