wrong extra file extension (html) when exporting pictures

When I export pictures from my Android to my Mac (AirDroid 1.0.5 beta) , the exported files are received on the Mac as a normal Downloaded file in the browser of the Mac (Safari) and get an extra file extension type .html, which does not work, when trying to open it. When I change the extension xxx.jpg.html to xxx.jpg on my Mac the pictures is shown as it should.