Responsify WP is the WordPress plugin that cares about responsive images.

Features

• Use img with srcset/sizes attributes.
• …or the picture element.
• Works with or without Picturefill.
• Supports high resolution images (retina).
• Custom media queries.
• Handpick which image sizes to use.
• Responsive background images.

Demo

Responsify WP finds featured images and all images inside the content and makes them responsive.
For example, you might have a template that looks like this:

That will output something like this:

    
Hello world
    
Lorem ipsum dolor sit amet...
    

But once you have activated the plugin, it will look like this instead:

    
Hello world
    
Lorem ipsum dolor sit amet...
    

You can also choose to use the picture element instead:

    
Hello world
    
Lorem ipsum dolor sit amet...
    
        
        
        
        
    

It also works with high resolution (retina) images:

    
Hello world
    
Lorem ipsum dolor sit amet...
    
        
        
        
        
    

The different versions of the image in the examples above is in the standard thumbnail, medium, large and full sizes.
The media queries are based on the width of the “previous” image.
Any custom sizes of the image will also be found and used.

Settings

You can select which image sizes that the plugin should use from the RWP settings page.
These settings can be overwritten from your templates.

 'portfolio',
    'rwp_settings' => array(
        'sizes' => array('large', 'full')
    )
) );
foreach( $posts as $post ) {
    // ...
}

// Using WP_Query()
$query = new WP_Query( array(
    'category_name' => 'wordpress',
    'rwp_settings' => array(
        'sizes' => array('large', 'full')
    )
) );
if ( $query->have_posts() ) {
    // ...
}
?>

Available settings:

• Select which image sizes to use.
• Set/override attributes.
• Set custom media queries.
• Turn on/off retina.
• Ignore image formats.

Functions

RWP provides a number of functions that can generate responsive images in your templates.
Let’s say that you have the following markup for a very large header image:

As you probably know, the_post_thumbnail() will create a regular tag with the full-size image in this case.
But you don’t want to send a big 1440px image to a mobile device. This can easily be solved like this:

    ID );

    // Generate an  tag with srcset/sizes attributes.
    echo rwp_img( $thumbnail_id );

    // Generate a  element
    echo rwp_picture( $thumbnail_id );
    ?>

Website

http://responsifywp.com.

Demo

http://responsifywp.com/demo.

Documentation and examples

https://github.com/stefanledin/responsify-wp.

Requirements

• PHP 5.3

Using The WordPress Dashboard

1. Navigate to the ‘Add New’ in the plugins dashboard
2. Search for ‘Responsify WP’
3. Click ‘Install Now’
4. Activate the plugin on the Plugin dashboard

Uploading in WordPress Dashboard

1. Navigate to the ‘Add New’ in the plugins dashboard
2. Navigate to the ‘Upload’ area
3. Select responsify-wp.zip from your computer
4. Click ‘Install Now’
5. Activate the plugin in the Plugin dashboard

Using FTP

1. Download responsify-wp.zip
2. Extract the responsify-wp directory to your computer
3. Upload the responsify-wp directory to the /wp-content/plugins/ directory
4. Activate the plugin in the Plugin dashboard

Installation Instructions

Using The WordPress Dashboard

1. Navigate to the ‘Add New’ in the plugins dashboard
2. Search for ‘Responsify WP’
3. Click ‘Install Now’
4. Activate the plugin on the Plugin dashboard

Uploading in WordPress Dashboard

1. Navigate to the ‘Add New’ in the plugins dashboard
2. Navigate to the ‘Upload’ area
3. Select responsify-wp.zip from your computer
4. Click ‘Install Now’
5. Activate the plugin in the Plugin dashboard

Using FTP

1. Download responsify-wp.zip
2. Extract the responsify-wp directory to your computer
3. Upload the responsify-wp directory to the /wp-content/plugins/ directory
4. Activate the plugin in the Plugin dashboard

1. 

   Select which filters that RWP should be applied on. Thumbnails (post_thumbnail_html) and content (the_content) is used by default.You can also select which markup pattern RWP should generate.

2. 
3. 

   You can easily override the default media queries for each image size. You can specify different settings for different scenarios.

4. 
5. 

1.9.11

• Minor updates.

1.9.10

• Fix for the “E_NOTICE: Undefined index ‘full'” error message. Thx to Jesse Norell!

1.9.9

• Fixed for the “E_WARNING: Illegal string offset ‘width'” error message. Thx to John Gadbois!

1.9.8

• Renamed the Logger class to Responsify_WP_Logger. Thx to @victorsebrito!

1.9.7

• Fixed a bug in the Custom Media Queries interface.
• Support for WordPress 4.7

1.9.6

• Critical PHP 5.3 bugfix

1.9.5

• Bugfix. All image sizes was used if the one inserted through the editor wasn’t selected by the user.

1.9.4

• Bugfix, Custom Media Queries.
• Support for WordPress 4.4

1.9.3

• Updated the Picturefill polyfill to version 3.0.1.

1.9.2

• New feature: Debug mode. RWP adds an HTML comment with information about the image.
• Bugfix. Retina + specified image.
• Bugfix. The rwp_edit_generated_element filter is applied when calling rwp_img() and rwp_picture().

1.9.1

• Bugfix for the custom media query interface in Safari.
• The ability to deselect the full image size is back. (Accidentally removed in RWP 1.9)
• Minor improvements.

1.9.0

• Introducing a brand new user interface for managing custom media queries for the images.
• New filter: rwp_edit_generated_element. It allows you to make changes to the generated element before it’s inserted into the content.
• Tested with WordPress 4.3 beta 3.
• Improvements under the hood.

1.8.0

• Picture::create() has been replaced by rwp_img(), rwp_picture(), rwp_span(), rwp_style() and rwp_attributes(). (Picture::create() will still work)
• New filter: rwp_edit_attributes. It allows you to edit the attributes before they are applied to the generated element.
• Picturefill has been upgraded to version 2.3.1.
• Bugfixes and improvements.
• Tested with WordPress 4.2
• Thanks to @mawosch for the help with this release.

1.7.3

• Picture::create(‘attributes’) works with custom settings now.
• Bugfix: RWP should not be applied on RSS feeds.

1.7.2

• New: RWP will ignore images with the ‘rwp-not-responsive’ class.
• Bugfixes.

1.7.1

• Bugfix. The $content_width variable in functions.php could make the generated markup to be slightly incorret.

1.7.0

• Works on featured images out of the box.
• Apply RWP on custom content filters using the rwp_add_filters filter.
• Support for high resolution (retina) images.
• Picture::create(‘attributes’) returns only the generated attributes.

1.6.5

• Critical PHP 5.3 bugfix

1.6.4

• Bugfix. The default value of the sizes attribute didn’t work as expected in browsers with native support.
• Minor bugfixes and improvements.
• Added the ability to disable Picturefill.

1.6.3

• Updated Picturefill to version 2.2.0
• Minor bugfixes
• Tested with WordPress 4.1

1.6.2

• Added the ability to ignore image formats.
• Bugfixes.

1.6.1

• Critical bugfix. If the picture element was selected before 1.6.0, it stopped working.

1.6.0

• RWP now supports the sizes/srcset attributes. It’s the new default markup pattern.
• Bugfixes and improvements.

1.5.2

• Bugfix. Custom media queries works with the picture element now.

1.5.1

• All attributes on the original img tag are now preserved and passed on to the new element.
• External images will be ignored.
• Bugfixes
• Thanks to habannah for all of her help with pointing out issues with RWP.

1.5.0

• Now it’s possible to select if you want to use span or the real picture element.
• It’s also possible to only use the Picture::create() without replacing any img tags in the content.
• Bugfixes.

1.4.3

• Bugfix. If an image is beeing inserted by a shortcode, the generated markup could be replaced.

1.4.2

• Bugfix. On PHP 5.3.28, the plugin could make the site crash. Not anymore!

1.4.1

• Bugfix. If an image doesn’t exists in a selected size, WordPress returns the full size image instead. That would break the media queries.
• Tested with WordPress 4 beta 2.
• Improved documentation.

1.4

• Now it’s possible to set custom media queries.

1.3

• Settings can be passed in the query.

1.2

• The content filter now works on PHP 5.3