Wordpress 'Illegal string offset' after updates - php

Question

My new client has a website that hadn't been updated in a long time. Now the PHP version, wordpress version and plugins are all up to date, but the Portifolio items now return this error:
Screenshot:
Warning: Illegal string offset 'alt' in
/home/elite856/public_html/wp-content/themes/eliteled/functions.php on
line 679
Warning: Illegal string offset 'url' in
/home/elite856/public_html/wp-content/themes/eliteled/functions.php on
line 679
This is line 679:
'<img src="'. $ob_img['url'] .'" class="capa" alt="'. $ob_img['alt'] .'" />'.
This is the whole function:
$portfolio = new WP_Query( $args );
if( $portfolio->have_posts() ){
while ( $portfolio->have_posts() ) { $portfolio->the_post();
$ob_img = get_field( 'imagem_de_capa' );
$allcats = get_the_category( get_the_ID() );
$cat = $allcats[0]->name;
$arrayData = array(
'id' => get_the_ID(),
'Titulo' => get_the_title(),
'cat' => $cat
);
//Criando arrayData com as informações do portfolio
if( have_rows('conteudo_do_portfolio') ){
while( have_rows('conteudo_do_portfolio') ){ the_row();
$tipo = get_field( 'tipo' );
if( $tipo == 'foto' ){
if( empty( $arrayData['imgs'] ) ){
$arrayData['imgs'][] = array(
'full' => $ob_img['original_image']['url'],
'thumb' => wp_get_attachment_image_src( $ob_img['id'], 'thumb_portfolio' )[0]
);
}
$idImg = get_sub_field('foto');
$arrayData['imgs'][] = array(
'full' => wp_get_attachment_image_src( $idImg, 'full' )[0],
'thumb' => wp_get_attachment_image_src( $idImg, 'thumb_portfolio' )[0]
);
}else{
$idVideo = youtube_video_id( get_sub_field('video') );
$arrayData['imgs'][] = array(
'full' => $idVideo,
'thumb' => "http://img.youtube.com/vi/{$idVideo}/0.jpg"
);
}
}
}
//'<li class="'. ( is_home() || is_front_page() ? 'item-home' : '' ) .'">'
$conteudo .= '<li>'.
'<img src="'. $ob_img['url'] .'" class="capa" alt="'. $ob_img['alt'] .'" />'.
'<div class="camada text-center">'.
'<a href="#" class="openModalPortfolio" data-tipo="'. get_field( 'tipo' ) .'" data-json=\''. json_encode( $arrayData ) .' \'\ >'.
//'<div class="'. ( is_home() || is_front_page() ? 'center-home' : 'center' ) .'">'.
'<div class="center">'.
//'<img src="/wp-content/themes/eliteled/images/expand'. ( is_home() || is_front_page() ? '' : '-red' ) .'.png" class="expand" />'.
'<img src="/wp-content/themes/eliteled/images/expand-red.png" class="expand" />'.
'<span class="titulo">'. ( strlen( get_the_title() ) > 60 ? substr( get_the_title(), 0, 60 ) . '...' : get_the_title() ) .'</span>'.
'<span class="cat">'. $cat .'</span>'.
'</div>'.
'</a>'.
'</div>'.
'<div class="camada camada-branca"></div>'.
'</li>';
}
}
I've read that this warning used to not be printed like that before PHP 5.4, and also that it happens because it was expecting and array. I got little PHP skills, can someone give me a clue about what to do?

Answer 1

Based from the dumped data, I am guessing the content of original_image is an attachment ID, so try this:
$img_params = json_decode($ob_img, true); // convert string to associative array
$url = wp_get_attachment_image_url($img_params['original_image']);
if ($url) {
// we have the image url now so display the image here tag here
}
if it doesn't work, check the original theme/plugin developer if there is new update to the plugin/theme where this portfolio came from