Uploading picture to the COVA application

For the last 2 days I have been trying to upload my picture to the COVA application. But keep coming back with the same error message "Your photo must be taken in front of a plain white or off-white background. Please choose a different photo." I have tried multiple pictures and even used a white bed sheet as a background, but will get the same error message. Is there a paper form application I can use, or can I do a walk-in appointment at the Chicago Embassy (since I live in Missouri) to apply for the China Tourist Visa?