How to wrap a anchor tag around image tag using Jekyll?

Question

I'm using WebLinkValidator to validate broken links and images in my website. But I'm using lazy loading for my images. All image source path saved in data-source attribute in the HTML tag as follows. But weblink validator doesn't validate my original image path.

<img src="default-image.png" data-source="original-image.png"/>

To overcome this issue I've planned to wrap a anchor tag around this image tag like below.

<a href="original-image.png">
   <img src="default-image.png" data-source="original-image.png"/>
</a>

For this I've used the below code in Jekyll plugin, but I cannot get the results

```

require 'kramdown' require 'nokogiri' module Jekyll class UpcaseConverter < Converter safe true priority :low

def matches(ext)
  ext =~ /^\.md$/i
end

def output_ext(ext)
  ".html"
end

def convert(content)
    content = convert(super(content))
end

def convert(content)
    doc = Nokogiri::HTML.fragment(content)
    doc.css('img').each do |image|
        image.wrap("<a href='"+ image['data-source'] +"'></a>")
    end

    return doc.to_s
end

end end

```