The image that you are trying to download is hosted on a server that uses some kind of hotlink protection. (you can only access it when you are active on certain webstites). unfortunately the nature of this addon makes it incompatible with these kinds of protection. instead of the image you got an error response that resulted in the empty file.

It is not perfectly clear to me what you are doing. I assume that the pop up "save as" dialog is throttling your workflow. You can turn this popup off and download the converted image directly. Open the settings using the converters browser button at the top right of the browser. Than navigate to the "generic" tab and change to advanced mode. There you can turn off the save as dialog. Also make sure the filename conflict action is set to unique (default) if you want to avoid automatic overwriting existing files. Hopefully this resolves your issue if not please let me know and I might b able to help you further.

could you be more specifi oin what you were doing and what you were expecting? if so I can help you or fix the problem with the addon.