Error when adding additional attributes

Oh, now I see. Media queries are written like that for the picture element. For img, you’re really only changing the sizes attribute, which you can set in the attributes array.

$rwp_attributes = array(
	'sizes' => array( 'thumbnail', 'medium', 'large' ),
	'retina' => true,
	'attributes' => array(
		'class'           => 'lazyload img-responsive',
		'data-sizes'      => 'auto',
		'data-parent-fit' => 'cover',
		'sizes' => '(min-width: 1540px) [image-lg-width]px, (min-width: 1000px) [image-lg-width]px, (min-width: 770px) [image-md-width]px, (min-width: 321px) [image-sm-width]px, [image-xs-width]px'
	)
);

I know it’s hard to understand the code above, but I think that this “formula” would do the trick. You just have to insert the sizes of your custom image sizes.

Really? You don’t have the old code in some other place?

Yeah you just have to add the image sizes that you wanna use. img just want to have a bunch of different images to choose from, it doesn’t care if it’s “retina” or not. picture however needs to have the original and retina image grouped together in the same <source> tag.

Haha, of course they are. Why would anything be easy? 😉

Okey, back to the drawing board. Can I get the code for your custom image sizes and dimensions for the built in sizes so I can recreate the scenario?
Twenty fifteen was the theme, right?

Thanks!
It works like a charm for me… I tested on a clean installation with twenty fifteen and standard RWP settings, beside of the picture element as markup pattern.

I uploaded an image and placed the following code above the loop in index.php:

<?php
echo rwp_img(6, array(
    'sizes' => array( 'image-xs', 'image-sm', 'image-md', 'image-lg', 'image-xlg' ),
    'retina' => true,
    'attributes' => array(
        'class'           => 'lazyload img-responsive',
        'data-sizes'      => 'auto',
        'data-parent-fit' => 'cover',
        'sizes' => '(min-width: 1540px) 1540px, (min-width: 1000px) 1000px, (min-width: 770px) 770px, (min-width: 321px) 500px, 385px'

    )
));
?>

Works perfectly!

What happens if you remove the settings array? Any errors then? And if you then add one option at the time into the settings array?

You could also add var_dump($mq); before line 43 in responsify-wp/includes/img.php and see what happens.
It should look like this then:

if ( isset($images[$i]['media_query']) ) {
    $mq = $images[$i]['media_query'];
    $attribute[] = '('.$mq['property'].': '.$mq['value'].') '.$images[$i]['width'].'px';
} else {
    $attribute[] = $images[$i]['width'].'px';
}

Isn’t it the retina sizes?