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  • BlurUp-Plugin: Copy style attribute (#764)
  • Fixes minor security issue with video-embed plugin (#764)
  • Built: Update dependencies (#774, #756)
  • Fixes diverse issues with old AMD module pattern (#780, #779)


  • Fix wrong window context under very rare SSR (fixes #717)
  • Fix Safari Back-Forward Cache issue with lazyloading image elements (fixes #711)
  • Add lazyload of autoplay videos to unveilhooks (fixes #697)


  • Fix visibility check (fixes #709)


  • Fix ratio calculation in rias plugin (fixed in #685 by tikotzky)
  • Make thumb size for youtube poster image in video-embed plugin configurable (see #681 thx to @nikitasol)


  • Allow import/execution in node environment
  • Use “hqdefault” for youtube poster image in video-embed plugin fixes #666


  • Use width/height content attributes to detect physical aspect ratio of image candidates, if data-aspectratio and h/w descriptors are missing. #642
  • Do not leak global lazySizesConfig anymore fixes #647
  • Improve handling of cloned object-fit images fixes #648
  • Improve blur-up/effect plugin.
  • Add support fot native loading="lazy" feature as a native loading plugin.


  • Added the class ls-is-cached to already cached images.
  • Added h descriptor parsing fix plugin for MS edge (was already included in respimg polyfill.)
  • Effects-Plugin/Blur Up plugin: Remove [].find because IE…, fixes #631
  • Documentation stuff
  • Bring back *.min.js files to npm package, but don’t use them in your import/require. These are mostly for CDNs. Not for Common JS bundlers.


  • Blur Up plugin: make blur up mode configurable by script
  • Unload Plugin: Fix unload plugin not knowing current expand, fixes #608
  • simplify resetPreloading and switchLoadingClass, fixes #614


  • Several Readme fixes
  • Allow expand, hFax and expFactor to be changed after initialization, see #581


  • Blur Up plugin: Add an empty alt attribute to the blur image to satisfy a11y c3256d6
  • Blur Up plugin: added aria-hidden attribute 1d62efb
  • RiaS plugin: fix wrong ratio calculation, fixes #550
  • Rias Plugin: add aspect-ratio to rias for calculating height, fixes #557


  • Resolve race condition with blurImg dffa93b
  • make intersectionobserver version compatible with plugins 2f1a025


  • change from custom to basic event interface (maybe fixes #520)
  • Clarify data-aspectratio attribute d868605


  • fixes race condition with blurupimg #527
  • add proxy change event to extend bgset #532



  • improve effect plugin


  • fixes issue in bgset introduced with version 4.0.3



  • 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.