It depends on the size of the container whether it's going to scale up or down. If it scales up it's going to likely be pixelated with an image like that as it has a lot of fine details. So even 1000x200 will pixelate if it has to scale up the width to cover the background. You could try doubling the maximum height/width settings and re-upload. So have the following for example.
Maximum Image Height: 1280
Maximum Image Width: 2560
Shouldn't need to do the same for thumbnail, but you can if you want to. But if you're using a fluid template for example and the component output within your template is like 2000px it's going to scale up if the width isn't 2000px and you'll get pixilation. There just isn't any avoiding this.
Upping the Maximum Image Height & Width seems have done the trick! Thank you!