Open your calendar in Microsoft Word. Once you have it open, it will prompt you for the month you want to view and if you want it to be different, feel free to change the value and continue.
Now that the calendar is open and ready for editing, we can choose change the image for the calendar header. Click on the image to select it and then right click it to get the Change Picture option.
Click the Change Picture menu item and choose where you would like to select the replacement picture from.
Once you insert it, your calendar will be updated with the new image and you are ready to save, print, or share it.