I just noticed this warning after a recent Drupal 7 core update, I don't believe it was there before.
Message: sites/all/themes/seven_doublemthemes/images/variant 4/body-background-tablet.jpg
I'm not sure why this code is looking in folder ".../variant 204/" as it doesn't exist. There is a folder ".../variant 2" with that file.
Thanks in advance for your help.