Upload Help

Hey there , I've had a problem with one of my pictures. I tried to upload a picture using the Admin CP options and even though it was saved as a .png the url I would be given by servimg would be a .jpg. I don't know if I'm doing something wrong here but I tried multiple times and nothing's helped, it always comes out as a .jpg, what would be causing this?

Is there a problem with the end result of the image?