If your prototype, or your website have low resolution/blurry images, while in Sketch they are much sharper:

  1. On Sketch, select the blurry image layer
  2. Find the Exportable preset panel in Sketch bottom-right
  3. For Retina - Mark the Exportable asset as @2x
    For Vector - Mark the Exportable asset as @1x, SVG 
  4. Preview in Browser to view results

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