When receiving a file upload on google app engine, the example assumes you\'re receiving a .png. However you only konw what the type of the image is by the extension on the
The filename of the file that is being uploaded can be determined by looking at the filename property of the variable that holds the file. For example, let's say that your form has a field named content:
Inside your Handler, you could find the name of the file with:
filename = self.request.POST["content"].filename