Distorted or Squashed?
Seems like the image has been scaled to a designated size rather than scaled and cropped.
ie: if an original image is 2000 x 1500 and needs to be resized to fit a 1000 x 500 box then we are dealing with images which have different w/h ratios.
Acknowledging this there would need to be a scale down to 1000 x 750 first (maintaining image ratio), then a crop to 1000 x 500 to achieve the desired size.
Image is fuzzy or pixelated?
If you find that the image is fuzzy it sounds like it is being scaled up. An image size should never be increased (not just for websites, in any scenario) as you can not maintain the original image quality, resulting in pixelation.