Generating dynamic thumbnail images

Oct 13, 2025 by wbrum.org 4 views

Proposal

In this article, we will explore the possibility of adding a template to customize OpenGraph image values in Typo. This feature will allow users to plug in their dynamic OpenGraph image generator services or even use Hugo to generate thumbnail images. We will discuss the current implementation of OpenGraph image rendering in Typo and propose a solution to make it more flexible and customizable.

Context

OpenGraph image is a crucial metadata tag used by social media platforms to display a thumbnail image when sharing a URL. The image is often dynamically generated by the platform, but users can also provide their own image by associating it with the URL. In Typo, the current implementation of OpenGraph image rendering uses Hugo's _internal/opengraph.html template, which does a decent job of picking an image by iterating through images provided in the frontmatter and images embedded in the article.

However, this implementation has some limitations. For example, it doesn't allow for generating a dynamic thumbnail like how GitHub does. Authors will need to manually embed some image into each article or edit the front-matter to add images, which is not desirable when you have a way to generate dynamic images with post title, author name, etc.

Current Implementation

The current implementation of OpenGraph image rendering in Typo uses Hugo's _internal/opengraph.html template. This template iterates through images provided in the frontmatter and images embedded in the article to pick an image. While this is fine for articles that have images, it doesn't allow for generating a dynamic thumbnail like how GitHub does.

Here is an example of how the current implementation looks like:

{{- with partial "_funcs/get-page-images" . }}
  {{- range . | first 6 }}
    <meta property="og:image" content="{{ .Permalink }}">
  {{- end }}
{{- else -}}
  {{- if .IsPage -}}
    <meta property="og:image" content="/api/og-image?url={{ .Permalink | urlquery }}">
  {{- end -}}
{{- end }}

This code uses a Cloudflare Worker to generate OpenGraph images dynamically if no other images exist for a given post.

Proposal

To make OpenGraph image rendering more flexible and customizable, we propose adding a new partial layouts/partials/head/og-image.html that will allow users to plug in their dynamic OpenGraph image generator services or even use Hugo to generate thumbnail images.

The og-image partial could either:

Allow for generating the whole <meta> tag. Onus is one the user to copy over existing Hugo implementation if they desire to.
Only allow generating the attribute value to be inserted into content which preserves existing Hugo behavior but less flexible.

We are leaning towards option (1), which will allow users to generate the whole <meta> tag.

Implementation

To implement this proposal, we will need to create a new partial layouts/partials/head/og-image.html that will contain the code for generating OpenGraph images. This partial will need to be customizable, allowing users to plug in their dynamic OpenGraph image generator services or even use Hugo to generate thumbnail images.

Here is an example of how the new partial could look like:

{{- with partial "_funcs/get-page-images" . }}
  {{- range . | first 6 }}
    <meta property="og:image" content="{{ .Permalink }}">
  {{- end }}
{{- else -}}
  {{- if .IsPage -}}
    <meta property="og:image" content="/api/og-image?url={{ .Permalink | urlquery }}">
  {{- end -}}
{{- end }}

This code is similar to the current implementation, but it will be moved to a new partial layouts/partials/head/og-image.html that will be customizable.

Benefits

The proposed solution will have several benefits, including:

Flexibility: Users will be able to plug in their dynamic OpenGraph image generator services or even use Hugo to generate thumbnail images.
Customizability: Users will be able to customize the OpenGraph image rendering to their needs.
Improved user experience: Users will be able to generate high-quality OpenGraph images that will improve the user experience when sharing URLs on social media platforms.

Conclusion

Q: What is OpenGraph image and why is it important?

A: OpenGraph image is a metadata tag used by social media platforms to display a thumbnail image when sharing a URL. It is an important aspect of social media optimization (SMO) and can significantly improve the user experience when sharing URLs on social media platforms.

Q: Why is the current implementation of OpenGraph image rendering in Typo limited?

A: The current implementation of OpenGraph image rendering in Typo uses Hugo's _internal/opengraph.html template, which does a decent job of picking an image by iterating through images provided in the frontmatter and images embedded in the article. However, this implementation has some limitations, such as not allowing for generating a dynamic thumbnail like how GitHub does.

Q: What are the benefits of customizing OpenGraph image values in Typo?

A: Customizing OpenGraph image values in Typo will make it more flexible and customizable. This feature will allow users to plug in their dynamic OpenGraph image generator services or even use Hugo to generate thumbnail images. It will also improve the user experience when sharing URLs on social media platforms.

Q: How will the new partial `layouts/partials/head/og-image.html` be customizable?

A: The new partial layouts/partials/head/og-image.html will be customizable, allowing users to plug in their dynamic OpenGraph image generator services or even use Hugo to generate thumbnail images. Users will be able to customize the OpenGraph image rendering to their needs.

Q: What are the possible use cases for customizing OpenGraph image values in Typo?

A: There are several possible use cases for customizing OpenGraph image values in Typo, including:

Generating dynamic thumbnail images: Users can use Hugo to generate thumbnail images based on the post title, author name, etc.
Plugging in dynamic OpenGraph image generator services: Users can plug in their dynamic OpenGraph image generator services to generate high-quality OpenGraph images.
Customizing OpenGraph image rendering: Users can customize the OpenGraph image rendering to their needs, such as changing the image size, format, etc.

Q: How will the new implementation of OpenGraph image rendering in Typo affect the user experience?

A: The new implementation of OpenGraph image rendering in Typo will improve the user experience when sharing URLs on social media platforms. Users will be able to generate high-quality OpenGraph images that will improve the user experience.

Q: What are the next steps for implementing the new partial `layouts/partials/head/og-image.html`?

A: The next steps for implementing the new partial layouts/partials/head/og-image.html include:

Creating the new partial: Create a new partial layouts/partials/head/og-image.html that will contain the code for generating OpenGraph images.
Customizing the partial: Customize the new partial to allow users to plug in their dynamic OpenGraph image generator services or even use Hugo to generate thumbnail images.
Testing the new implementation: Test the new implementation of OpenGraph image rendering in Typo to ensure that it works as expected.

Q: What are the benefits of using Hugo to generate thumbnail images?

A: Using Hugo to generate thumbnail images has several benefits, including:

Improved user experience: Hugo can generate high-quality thumbnail images that will improve the user experience when sharing URLs on social media platforms.
Flexibility: Hugo can generate thumbnail images based on the post title, author name, etc.
Customizability: Hugo can be customized to generate thumbnail images in different formats, sizes, etc.

Q: What are the possible challenges of customizing OpenGraph image values in Typo?

A: There are several possible challenges of customizing OpenGraph image values in Typo, including:

Complexity: Customizing OpenGraph image values in Typo can be complex, especially for users who are not familiar with Hugo or Typo.
Compatibility issues: Customizing OpenGraph image values in Typo may cause compatibility issues with other plugins or themes.
Performance issues: Customizing OpenGraph image values in Typo may cause performance issues, especially if the new implementation is not optimized.