The Largest Professional Oil Painting

Worlds Largest Oil Painting is an official Guinness World Record!

http://www.guinnessworldrecords.com/world-records/381329-largest-professional-oil-painting-by-a-single-artist
The  largest  professional  oil  painting
  by  a  single  artist  is  22.76    (245  ft²  20  in²), 
achieved  by  Gurmej  Singh AKA Artist SinGh (USA),
  at  the  Epic  Center
  in  Kalamazoo,  Michigan,  USA,
  on  8  September  2017.