Give each photo or JPG file a number in the order you want them to appear on the MLS.  The front photo of your home should be "photo1.jpg" for example, then "photo2.jpg".   If you do not number your photos, they will upload to the MLS in a random order (which you will not like).  The MLS automatically feeds the other real estate websites within 24-48 hours.   I have no control over these 3rd party websites.    Once your photos have been uploaded to the MLS there is a $50 fee to change or update your photos to the MLS!!!
If you would like to udate some or all of your photos on the MLS be sure to go to the "Seller Info" tab at the top of the website and select "Upgrade Options" and then select "Photo Change out" for $50.