Holder.js is described as 'Holder renders image placeholders entirely in browser. Placeholders can have custom colors, fonts, resizing behavior, and rendering engine (Canvas/SVG)' and is an app in the Development category. There are more than 10 alternatives to Holder.js for a variety of platforms, including Online / Web-based, SaaS, Wordpress, Flickr and Mac. The best alternative is Unsplash, which is free. Other great apps like Holder.js are Lorem Picsum (Free, Open Source), freeimages (Free), Placehold.it (Free) and satyr.io (Free).
Lorem Picsum provides an easy way for web developers to get elegant placeholder images. API access is available through simple and intuitive urls like picsum.photos/200/300 for a random 200px x 300px image.
Placeholder Images for every case. Webdesign or Print. It's simple and absolutely free! Just put the custom url in your code like this:<img src="http://lorempixel.com/400/200" />to get your FPO / dummy image.