Royal College of Art Poster Archive

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* fixes issue in bgset introduced with version 4.0.3


* add [blur up plugin](


* make all plugins CommonJS compatible (thx to @claudiobmgrtnr and @jantimon)
* added `loadHidden` option(thx to @justinvoelker)
* added artdirection plugin (no documentation yet, but great)
* iOS 8.1 fixes has to be loaded explicitly in non CommonJS environments (not included in respimg plugin anymore)
* removed `picture` support for old FF 38-


  • lazysizes core:
    • heavily improved performance (requestIdleCallback, better debouncing and a lot more).
  • plugins:


Breaking change: * the lazysizes.js and lazysizes.min.js files do not register as AMD modules anymore, if you need an AMD module use the new lazysizes-umd.js or lazysizes-umd.min.js file.

  • lazysizes core:
    • improved lazyloading in background tabs.
    • fixed set lazyloaded class to early in FF.
  • bgset/parentFit plugin:
    • improved avoiding layout thrashing.
  • respimg/bgset/parentFit plugin:
    • fixed bug in Edge 14 to parse height descriptors correctly.
  • unload plugin: unload plugin was broken since version 1.4.0 (thanks to @hokamoto)


  • lazysizes core:
    • improved lazyloading in background tabs.
    • improved avoiding layout thrashing
    • support of SVG elements (svg/image/use…)
  • bgset/parentFit plugin:
    • improved avoiding layout thrashing
  • rias (and bgset):
    • added support for height calculation (thx to @LRancez, #213)


  • lazysizes core:
    • add hFactor option (see #181).
  • unload plugin:
    • simplified unloadPixelThreshold calculation.
  • bgset plugin:
    • add an empty alt to image (see #200).

1.3.1 version

  • lazysizes core:
    • replace setImmediate with setTimeout (improved performance for IE/EDGE).
  • plugins:
    • fixed conflict with respimg plugin in combination with bgset plugin, in case of art direction and resize to smaller.
    • fixed conflict with RIaS plugin in combination with respimg plugin/picturefill in Safari 8/9.