Given code hides post images but keeps thumbnail image in Category archive and homepage. Add following code block in your theme’s function.php:

function wpi_image_content_filter($content){

if (is_home() || is_front_page() || is_category()){
$content = preg_replace(“/<img[^>]+>/i”, “”, $content);
}

return $content;
}
add_filter(‘the_content’,’wpi_image_content_filter’,11);