How do you create a thumbnail with Kirby?
The most common is probably by using the thumb function like this:
<?= thumb($page->image($page->my_image()), array('width' => 300)); ?>https://getkirby.com/docs/cheatsheet/helpers/thumb
We need to wrap everything with a thumb function. To use a particular filename, we also need to wrap $page->my_image() inside $page->image(), else it will pick the first image. It's not very straight forward.
To use toFile is a "new" way of working with thumbs. It's in the docs but not very prominent.
It looks much simpler:
<?= $page->my_image()->toFile()->resize(300); ?>To check if the file exists we can do this:
<?= ($image = $page->my_image()->toFile()) ? $image->resize(300) : ''; ?>In the above, we check if $page->my_image()->toFile() exists and if it does, put it into $image. Then $image is used to resize the thumb. If it does not match, don't write anything. It may look complicated, but this way we can get away with a oneliner.