I have a photo but its been so long since I have uploaded one I have forgotten what to do!!
Click on Gallery and select Upload File. Make sure the image is 1mb or less and the longest side size is 2048 or less. From the new window select where you want to upload the file to, in this case weekly competition folder, then select the folder where the file is and click on the file then upload. When uploaded fill out the fields and select save. Job done.