Tornado max-message-size for Bokeh Webapp

For an application I am building that used bitmap images, I have created a webapp that allows the user to upload images using Bokeh's FileInput widget.

The problem is that the images needed for this application exceed Tornado's max-message-size property. This can normally be adjusted if a Bokeh Server is launched from the command line or in the configuration file of Tornado. For this Bokeh Webapp using a virtual environment, neither is an option. Does anyone have a suggestion how to change this max-message-size property for Bokeh Webapps?