How do you set the rendering size? How do you size the camera to fit the size needed on the youtube channel art? It says it's too small when I upload the image. I need to make the camera at least 2048 x 1152 pixels. It would be nice to have it at 2560 x 1440 pixels though. I tried the other questions, but it didn't make it any wider than it was before. The Y and X values under Resolution in Dimensions Under Render Settings just made the camera taller.
Set the desired size for the rendered scene in Scene->Dimensions->Resolution:



Then render using F12 and save the resulting image