将img标签转换为amp-img的最佳方式是什么？

I have a wordpress website and the images that come from the the_content() function have the <img> tag, however for the AMP pages they should be written like this: <amp-img>. What's the correct way of doing that in WP?

Try with this:

add_filter('the_content', 'change_img', 99);
function change_img( $content )
{
    return str_replace('<img', '<amp-img', $content);
}

I would build a php function which replaces "img" with "amp-img".

<?php 
function parseTagsIntoAmpTagsFromString($string)
{
    $search = ["<img", "</img>"];
    $replace = ["<amp-img", "</amp-img>"];
    return str_replace($search, $replace, $string);
}
?>

As the code above shows, you will need to match starting and closing tags. The replacement is done on the found keys in $search and $replace.