Image Processing crashes on building a website

[junkpiano]

I am trying to process images by using shortcode imgproc.html, but it crashes when building my blog.

My code is

{{< imgproc "/images/sample-image.jpg" Resize "250x" left >}}

The error message says that

execute of template failed: template: shortcodes/imgproc.html:9:36: executing "shortcodes/imgproc.html" at <$original.Resize>: nil pointer evaluating resource.Resource.Resize

It seems it fails to fetch and assign the original image.

Another shortcode like image works, so the image path is correct.