Resize external image

Is there a way to resize an image with an external url? When I try to do the following:

<?php $image = "" ?>
<img src="<?= $image->resize(200)?>"/>

I of course get Call to a member function resize() on string

Probably need to get hold of it with F::read and store it locally, then youll be able to pick it up and turn into a file object

Or you would have to go the virtual files route: Virtual files | Kirby CMS

Thank you both for your suggestions. In your option, what would be easier in this case? I only want to resize the image, not much else.

Just one image?

Well on second thought it might be more complicated. I would like to resize images from an RSS-Feed. I have a model that creates virtual pages and the RSS-Feed contains images that are very large.