Blur up image inline styles are lost

Describe the bug When using the blur up plugin, the inline style set for the images are lost during the plugin execution.

Steps to reproduce the behavior:

1. Use the blur-up plugin for lazysizes.
2. Set inline styles on an Image element (e.g.: aspect-ration: 1 / 1;)
3. Add blur-up and lazyload classes to the element
4. After blur up finishes, the inline styles are lost

What is the expected behavior: The CSS properties should be preserved.

What happened instead: The CSS properties are getting lost.

Root cause At https://github.com/aFarkas/lazysizes/blob/gh-pages/plugins/blur-up/ls.blur-up.js#L111C4-L111C11

The following line

blurImg.cssText = img.cssText;

should be instead:

blurImg.style.cssText = img.style.cssText;

cssText is a property of style attribute of the element, not the element itself. See: https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleDeclaration/cssText

Workaround As a workaround, it is possible to set up the cssText attribute for the HTMLImageElement to proxy the element.style.cssText attribute:

  Object.defineProperty(window.HTMLImageElement.prototype, 'cssText', {
    get() {
      return this.style.cssText;
    },
    set(newCssText) {
      this.style.cssText = newCssText;
    },
  });