Related question I am having similar problems to what that guy had in his. My upload server returns aredirect Specifically, I am not sure what FormPanel.SubmitCompleteEvent.getResults() returns. Sometimes, I get html of an img: <img style="cursor: -moz-zoom-in;" alt="http://<myapp>.appspot.com/servePic?blob-key=abcdef" src="http://<myapp>.appspot.com/servePic?blob-abcdef" height="1" width="1"> Sometimes I get the image data in bytes. Behavior varies on I dunno what. I get the first in development, and the second in production. Does anyone know anything about this?