# WebP Express

Serve autogenerated WebP images instead of jpeg/png to browsers that supports WebP. Works on anything (media library, galleries, theme images etc).

The plugin is available on the Wordpress codex ([here](https://wordpress.org/plugins/webp-express/)), and developed on github ([here](https://github.com/rosell-dk/webp-express/)).

## Description
Almost 4 out of 5 mobile users use a browser that is able to display webp images. Yet, on most websites, they are served jpeg images, which are typically double the size of webp images for a given quality. What a waste of bandwidth! This plugin was created to help remedy that situation. With little effort, Wordpress admins can have their site serving autogenerated webp images to browsers that supports it, while still serving jpeg and png files to browsers that does not support webp.

The plugin basically routes jpeg/png images to an image converter, or - if the image converter has already converted the image - directly to a converted image. The approach has the benefit that is works regardless of how an image found its way into your server - be it Media Library, Galleries, or even theme images referenced with CSS.

The plugin builds on [WebPConvert](https://github.com/rosell-dk/webp-convert) and its "WebP On Demand" solution described [here](https://github.com/rosell-dk/webp-convert/blob/master/docs/webp-on-demand/webp-on-demand.md)

#### Benefits
- Much faster load time for images in blink based browsers such as Chrome and Opera (overall accounting for ~73% of all traffic, and ~78% of mobile browsing trafic, according to [caniuse.com](https://caniuse.com/webp)).
- The converted images are typically *less than half the size* (for jpeg), while maintaining the same quality. Bear in mind that for most web sites, images are responsible for the largest part of the waiting time.
- Better user experience (whether performance goes from terrible to bad, or from good to impressive, it is a benefit)
- Better ranking in Google searches (performance is taken into account by Google)
- Less bandwidth consumption - makes a huge difference in the parts of the world where the internet is slow and costly (you know, ~80% of the world population lives under these circumstances).


## Installation

1. Upload the plugin files to the `/wp-content/plugins/webp-express` directory, or install the plugin through the WordPress plugins screen directly.
2. Activate the plugin through the 'Plugins' screen in WordPress
3. Configure it (the plugin doesn't do anything until configured)
4. Verify that it works

### Configuring
You configure the plugin in *Settings > WebP Express*.

#### Conversion methods
WebP Express has a bunch of methods available for converting images: Executing cwebp binary, Gd extension, Imagick extension, ewww cloud converter and remote WebP express. Each requires *something*. In many cases, one of the conversion methods will be available. You can quickly identify which converters are working - there is a green icon next to them. Hovering conversion methods that are not working will show you what is wrong.

In case no conversion methods are working out of the box, you have several options:
- You can install this plugin on another website, which supports a local conversion method and connect to that using the "Remote WebP Express" conversion method
- You can [purchase a key](https://ewww.io/plans/) for the ewww cloud converter. They do not charge credits for webp conversions, so all you ever have to pay is the one dollar start-up fee :)
- You can set up [webp-convert-cloud-service](https://github.com/rosell-dk/webp-convert-cloud-service) on another server and connect to that. Its open source.
- You can try to meet the server requirements of cwebp, gd, imagick or gmagick. Check out [this wiki page](https://github.com/rosell-dk/webp-convert/wiki/Meeting-the-requirements-of-the-converters) on how to do that

### The auto quality
If your server has imagick og gmagick installed, the plugin will be able to detect the quality of a jpeg, and use the same quality for the converted webp. You can tell if it does, by looking at the quality option. If it allows you to select "auto" quality, it is available, otherwise it is not, and you will only have the option to set a specific quality for all conversions. *Auto* should be chosen, if available, as this ensures that each conversion are converted with an appropriate quality. Say you have a jpeg with low quality (say 30). The best result, is achieved by converting it to the same quality. Converting it with high quality (say 80), will not get you better quality, only a larger file.

If you do not the "auto" option available:
- Install imagick or gmagick, if you can
- Use "Remote WebP Express" converter to connect to a site, that *does* have the auto option available
- If you have cwebp converter available, you can configure it to aim for a certain reduction, rather than using the quality parameter. Set this to for example 50%, or even 45%.

### Verifying that it works.
Once, you have a converter, that works, when you click the "test"-button, you are ready to test the whole stack, and the rewrite rules. To do this, first make sure to select something other than "Do not convert any images!" in *Image types to convert*. Next, click "Save settings". This will save settings, as well as update the *.htaccess*.

If you are working in a browser that supports webp (ie Google Chrome), you will see a link "Convert test image (show debug)" after a successful save. Click that to test if it works. The screen should show a textual report of the conversion process. If it shows an image, it means that the *.htaccess* redirection isn't working. It may be that your server just needs some time. Some servers has set up caching. It could also be that your images are handled by nginx.

Note that the plugin does not change any HTML. In the HTML the image src is still set to ie "example.jpg". To verify that the plugin is working (without clicking the test button), do the following:

- Open the page in Google Chrome
- Right-click the page and choose "Inspect"
- Click the "Network" tab
- Reload the page
- Find a jpeg or png image in the list. In the "type" column, it should say "webp"

In order to test that the image is not being reconverted every time, look at the Response headers of the image. There should be a "X-WebP-Convert-Status" header. It should say "Serving existing converted image" the first time, but "Serving existing converted image" on subsequent requests (WebP-Express is based upon [WebP Convert](https://github.com/rosell-dk/webp-convert)).

You can also append `?debug` after any image url, in order to run a conversion, and see the conversion report. Also, if you append `?reconvert` after an image url, you will force a reconversion of the image.

### Notes

*Note:*
The redirect rules created in *.htaccess* are pointing to a PHP script. If you happen to change the url path of your plugins, the rules will have to be updated. The *.htaccess* also passes the path to wp-content (relative to document root) to the script, so the script knows where to find its configuration and where to store converted images. So again, if you move the wp-content folder, or perhaps moves Wordpress to a subfolder, the rules will have to be updated. As moving these things around is is a rare situation, WebP Express are not using any resources monitoring this. However, it will do the check when you visit the settings page.

*Note:*
Do not simply remove the plugin without deactivating it first. Deactivation takes care of removing the rules in the *.htaccess* file. With the rules there, but converter gone, your Google Chrome visitors will not see any jpeg images.

*Note:*
The plugin has not been tested in multisite configurations. It's on the roadmap...


## Limitations

* The plugin does not work on Microsoft IIS server
* The plugin has not been tested with multisite installation

## Frequently Asked Questions

### Why do I not see the option to set WebP quality to auto?
The option will only display, if your system is able to detect jpeg qualities. To make your server capable to do that, install *Imagick* or *Gmagick*

### How do I make this work with a CDN?
Chances are that the default setting of your CDN is not to forward any headers to your origin server. But the plugin needs the "Accept" header, because this is where the information is whether the browser accepts webp images or not. You will therefore have to make sure to configure your CDN to forward the "Accept" header.

The plugin takes care of setting the "Vary" HTTP header to "Accept" when routing WebP images. When the CDN sees this, it knows that the response varies, depending on the "Accept" header. The CDN is thus instructed not to cache the response on URL only, but also on the "Accept" header. This means that it will store an image for every accept header it meets. Luckily, there are (not that many variants for images)[https://developer.mozilla.org/en-US/docs/Web/HTTP/Content_negotiation/List_of_default_Accept_values#Values_for_an_image], so it is not an issue.

### How do I donate?
Putting this question in the "frequently" asked questions section is of course some mixture of humour, sarcasm and wishful thinking. In case there really is someone out there wanting to donate, you can simply write to me, and we can arrange. My contact information is available here https://www.bitwise-it.dk/contact. I have paypal, mobilepay and of course an ordinary bank account.

## Changes in 0.7.0
This version added option to provide conversion service to other sites!

For more info, see the closed issues on the 0.7.0 milestone on the github repository: https://github.com/rosell-dk/webp-express/issues?q=is%3Aclosed+milestone%3A0.7.0

## Silly dance-ware
If you enjoy this software, feel free to express yourself now through bodily movements. Don't - be - shy!

*No animals were harmed and no women were sexually harassed either during the production of this plugin*