Error with Image Size from Joss Sanglier Tuts

[Speed]

Hi Everyone,

As much I am trying to understand the core of PW, I've been following few other tuts including Joss Sanglier's basic webpage tutorial. It was easy to follow except the part where I could not solve problems with image size. Here's link https://processwire.com/docs/tutorials/simple-website-tutorials/the-basic-website/page5 see the "Writing the Panel Code" part. 

Here's my code... using KubeCSS foundation. 

<?php 
include("./includes/head.inc");
?>

<div class="row centered">
    <div class="col col-6">
        <div class="content">
            <h1><?php $page->title; ?></h1>
            <?php echo $page->ckeditor_1; ?>
        </div>
    </div>
</div>

<?php
    $panels = $pages->find("template=basic-page");
    foreach($panels as $panel);{
?>
    <div class="panels" style="background-color:<?php echo $panel->color_picker; ?>">
        <div class="row centered">
            <div class="col col-8">
                <div class="content">
                    <h2><?php echo $panel->title; ?></h2>
                    <?php echo $panel->ckeditor_2; ?>
                    <p class="readmore"><a href="<?php echo $panel->url; ?>">Read More</a></p>
                </div>
            </div>
            <div class="col col-8">
                <div class="content">
                <?php 
                   if($panel->image_single){
                   echo "<img src='{$panel->image_single->size(400,200)->url}' alt='{$panel->image_single->description}'>";
                   }
                ?>
                </div>
            </div>
        </div>
    </div>

    
    <?php } ?>
<?php
include("./includes/scripts.inc");
include("./includes/foot.inc");
?>

... and got error...

I've "debugged" part of code and noticed 

echo "<img src='{$panel->image_single->size(400,200)->url}' alt='{$panel->image_single->description}'>";

The size(400,200) is the problem! Can anyone help me resolve this issues. Thanks in advance

[adrian]

Is image_single set to a max of 1 image on the details tab?

[Speed]

Haha You rock!  Care to explain what exactly it does? 

[adrian]

5 minutes ago, Speed said:

Haha You rock!  Care to explain what exactly it does? 

Ah sorry - have a good read through this: https://processwire.com/api/fieldtypes/images/

But in essence, if it's not set to 1 then it returns an array of images, so you can either set to 1, or use this to get the first image. You can also use last() or eq(n) to specify a specific image.

$panel->image_single->first()->size(400,200)->url

[LostKobrakai]

The images field by default does return a list of images and you cannot call size() on a list, but only on a single image. By using the settings of the field you can alter that behavior to only return a single image directly.

[Speed]

It all make sense now! Thank you for guys for clarification.