//- Insert a WebP Image with Fallbacks  
mixin imgWebP(img, fallbackEnding, alt, selector)
  if (selector)
    picture(class='#{selector}')
      source(src='#{images}#{img}.webp', type='image/webp')
      case fallbackEnding
        when 'jpg'
          source(src='#{images}#{img}.jpg', type='image/jpg')
        when 'jpeg'
          source(src='#{images}#{img}.jpg', type='image/jpg')
        when 'gif'
          source(src='#{images}#{img}.gif', type='image/gif')
        when 'png'
          source(src='#{images}#{img}.png', type='image/png') 
      img(src='#{images}#{img}.jpg', alt='#{alt}')
  else
    picture
      source(src='#{images}#{img}.webp', type='image/webp')
      case fallbackEnding
        when 'jpg'
          source(src='#{images}#{img}.jpg', type='image/jpg')
        when 'jpeg'
          source(src='#{images}#{img}.jpg', type='image/jpg')
        when 'gif'
          source(src='#{images}#{img}.gif', type='image/gif')
        when 'png'
          source(src='#{images}#{img}.png', type='image/png') 
      img(src='#{images}#{img}.jpg', alt='#{alt}')