Given the lack of cross browser & inconsistent support for CSS clip-path & mask-image . This seemed like a solid simple approach.
Use jQuery to swap out the original IMG with an SVG equivalent.
SVG contains masking path. More about SVG
paths
.
Add 'data-mask' attribute to IMGs. Include svg path coords i.e. data-mask="M424.313,250.873c0..."
Tested in: IE9,10,11 & Edge. Chrome, Safari, Opera & FF. Android & iOS.
Non-JS users will see original image (Graceful Degradation)
Or only apply this technique to SVG supported browsers using Modernizer "if (Modernizr.inlinesvg) {}"
SVG contains title & desc elements for accessibility. See here
<img src="x.jpg" width="320" height="240" title="abc..." alt="abc..." data-mask="...">
becomes...
<svg version="1.1" xmlns="http://www.w3.org/2000/svg" class="svgMask" width="320" height="240" viewBox="0 0 320 240">
<defs><clipPath id="maskID0"><path d="..." /></clipPath></defs>
<title>abc...</title>
<desc>abc...</desc>
<image clip-path="url(#maskID0)" width="320" height="240" xlink:href="x.jpg" />
</svg>
Original rectangular image here
Follow: @jim_savage