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José M. Pérez, frontend developer at @Spotify wrote great article about using SVG as image placeholders [url=https://medium.freecodecamp.org/using-svg-as-placeholders-more-image-loading-techniques-bed1b810ab2c]https://medium.freecodecamp.org/using-svg-as-placeholders-more-image-loading-techniques-bed1b810ab2c[/url]
In Jan 2018 José M. Pérez has presentation at FrontFest conference called “Progressive Image Rendering” where he mentions SVG placeholder technique too, see [url=http://www.boardea.com/watch?v=xxh6mk60RDo]Oops, error 78 - Boardea.com - Displays YouTube video storyboard