I just use canva if my image is too small, I don’t have the premium version but I’m very happy with the free version, it’s super easy to use. not sponsored lol so I just log in and then click custom dimensions and type in the episode background requirements, I leave it blank on the picture then on the left side bar I upload the background of my choice and then tug on one of the corners so that I don’t stretch the image and it can keep its quality!
I can click on a new page so that I don’t have to keep searching for the size requirement!