Common Questions

Did you read the tutorial about this plugin already? If not, I suggest you read it first.

It creates the image files required by the Retina devices. In the case the resolution of the original images are not high enough, you will see a warning in the Media Library where you will be able to re-upload bigger images. The plugin then recognizes different devices and send the images required accordingly.
Have a look at this article.
The new images use the same name as your original files, with an “@2x” string added right before the extension. For example, if you have a Gundam-150×150.jpg file, a new Gundam-150×[email protected] will be created. Its size will be doubled. This naming convention actually comes from Apple.
Yes, check the Retina Dashboard screen (under the Media menu).
Yes, I suggest you strongly to use the YoImages plugin to crop your images.
No, the images are created through the standard WordPress process. If you wish to do this, have a look at my article on how to optimize images in WordPress.
You should have a look at my article about optimizing images in WordPress. Basically, it works with CDNs but with Amazon S3, not really (it depends on the plugin you are using for that).
Yes, if course! :)

Common Issues

Most issues are related to the sizes of your media. Make sure you read my article about Debugging Retina.

Maybe you are using a plugin that blocks the modification from being made. If you use a SEO plugin with a feature like Rewrite Post Title that might be it. Check this feature off and it will work.
The plugin can transform the images that go through the WordPress API and the ‘Image Sizes’ properly (which means that they are part of the Media Library). Themes often uses a one-time customized size for the logo, and for that reason the image wouldn’t be taken care of by the plugin. The easiest way to go around this is to create the Retina image by yourself. For example, if you are logo is 200×100 and named ‘logo.png’, upload a 400×200 version of that logo named ‘[email protected]’ next to the other one. It will work immediately.
Let’s say you have a logo which is 200×400. The retina logo would be 400*800, but it should STILL be shown as a 200×400 image relatively to the rest of your website. The workaround is to keep it simple and neat: always set the (normal) width and the height for all your images (in HTML directly or via CSS).
That is, unfortunately, the most infamous issue to expect with this new technology. A lot of developers ignore it still, sometimes don’t code properly, think that what they did is “enough”. You should ask the developer to do something about it, and if he cares, he will do it. You can also do it by yourself, check the next question. You can try to use the Meow Gallery, the slider works with Retina.
This is very tricky. The simple answer would be to ask yourself a developer or ask a good and very geeky friend. This is not a simple matter. If you are using Retina.js method, you can see how to resolve this issue on this Github discussion.
You could try using a re-writing rule in your WP Engine settings (HTML Post Processing). This regex would do the job:

#\S*.(?:jpe?g|png|gif|ttf|otf|svg|woff|js|css))# =>$1

Sometimes, themes and plugins developers will need to add support for the Retina. Using WP Retina 2x, it should be easy, I created functions, filters and actions for them.

Common Errors

Maybe you don’t have enough memory allocated to PHP or the script takes longer than the maximum execution time limit. You can change those values using the PHP Configuration File (php.ini):

* php_value memory_limit = “128M”;
* max_execution_time = 360;
… or by modifying the WordPress PHP files (wp-settings.php ideally):
* ini_set(‘memory_limit’, ‘512M’);
* ini_set(‘max_execution_time’, 300);

Please note that it doesn’t work with some cheap web hosts, as they don’t want you do to that instead. The real issue can also be tracked in the PHP error logs.
It is a known issue and it is not related to the plugin. You can find the answer on this post:
Sometimes, themes and plugins developers will need to add support for the Retina. Using WP Retina 2x, it should be easy, I created functions, filters and actions for them. Please find about this API here: