knuten

This plugin let you add a shortcode with two different image sources one too a normal sized image and one for retina. The plugin will then load the right image depending on if it’s a retina display or not. 
For more info and how to use it.
<h3>A brief Markdown Example</h3>
<pre><code>[retina normal="path-to-normal-image" retina="path-to-retina-image" width="image-width" height="image-height" /]
</code></pre>

Retina for WP

This plugin let you add a shortcode with two different image sources one too a normal sized image and one for retina.

David Favor

For now only occurrences of the <a href="http://imulus.github.io/retinajs" rel="nofollow ugc">retina.js</a> script are dequeue + deregister.
If you identify other Retina related scripts open a support ticket + note the name.
I’ll add any other identified scripts here, to strip them out also.
<h3>Problems Serving Retina Images</h3>
Some of these problems include…
<h4>Retina Image File Size + Mobile</h4>
Retina images have massive size. If you’re running a Food Porn blog or 
Image Hosting site, this might be okay.
Otherwise, likely your visitor on page time will decrease + conversions tank.
If you’re running a Click Arbitrage site or target Mobile devices, which 
may be on 3G networks or simply have under powered CPUs or little memory.
This occurs as size of Retina images eat up all your visitor’s connection 
bandwidth, then require heavy CPU + memory usage to render.
<h4>Retina Image 404s On Server</h4>
Most sites serving Retina images, do so via the horribly simplistic <a href="http://imulus.github.io/retinajs" rel="nofollow ugc">retina.js</a> library.
Unfortunately this script works by…
1) Extracting every DOM tag + rewriting the URL as 
 image-name@2X.extension back into the DOM.
2) For many sites 100% of these image-name@2X.extension file access 
 result in a 404 (missing page) error. Then <a href="http://imulus.github.io/retinajs" rel="nofollow ugc">retina.js</a> will walk 
 the DOM again, removing the @2X from images + the image file 
 fetch begins again. Since this process runs via AJAX, instantaneously 
 page load resource usage can spike very high.
3) WordPress caching plugins specifically avoid caching 404 errors. This 
 is intentional. The idea being, once you notice 404s, you’ll fix them. 
 If 404s were cached, every permanent + transient 404 error would 
 require a manual cache flush, to clear the cache object, so the fixed 
 page could then reach visitors.
4) Thus every 404 @2X image served generates what tends to be an extremely 
 high resource intensive page view… all for nothing…
5) If you have 20 images on a page you’ll generate 20x 404s.
You can see when this can lead to extreme dips in performance, 
which are hard to diagnose, unless you have a Server Savant 
doing daily log studies with logtop to monitor page view patterns.
Some servers where I host client sites showed 90%+ of all page 
accesses were 404s to Retina images.
As traffic spends or natural traffic increase, 404s increase, 
starving Apache + Database till eventually all visitors see become 
Apache 500 errors + Database Connection Errors.
<h3>Plugin History</h3>
This code was originally written to serve my many private hosting clients.
Check [http://FastStableHosting.com]http://FastStableHosting.com WordPress speedups.
This site is a work in process, where my goal is to converge all the many 
checklists I’ve published over the years cohesively + retire all other 
site with related WordPress performance boosting tips.
Material presented on this site is based on testing, rather than drivel + myth 
which pollutes the entire WordPress ecosystem, at every turn.
If you wonder why you keep reading how to speed up your site + nothing seems 
to make any difference, likely your reading content written by posers.

Retina Stripper

For now only occurrences of the retina.js script are dequeue + deregister.

Retina for WP vs Retina Stripper