I’m moving a conversation from the timeline over here for posterity and easier code sharing.
Is it possible to automatically use Micro.blog’s image scaling feature for all my images? Right now, there’s a lot of manual labor prepending https://micro.blog/photos/600x/to each image URL.
So Gunnar wants all his image URLs prefixed with https://micro.blog/photos/600x/ automatically. And that’s possible! But you have to use Markdown syntax when adding images in your posts. Markdown syntax looks like this:
But thanks to Hugo and something called Markdown Render Hooks we can override that behavior and render whatever we want. In this case, Gunnar wants HTML like this:
Enter the following path and filename layouts/_default/_markup/render-image.html. Naming is important, make sure it’s correct.
As content, paste the code snippet below and then click Update Template.
You’re done! Give your site time to rebuild. From now on, all images embedded with Markdown syntax should have the https://micro.blog/photos/600x/ prefix.
Content of layouts/_default/_markup/render-image.html:
This is a bare-bones example. There are a lot of bells and whistles you could potentially add, like support for width and height attributes, lazy loading, and so on.
Thank you @sod! My first one: - gunnar.se
And 173 KB is a lot better than 2.6 MB. And you get the full image if you click it.
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For another example of this, I implemented render hooks a while back in the glightbox plugin. I originally defaulted to using thumbnails, but ultimately didn’t like the quality that came out of Micro.blog’s resizing.
This is great! By the way, wherever you use a URL like “micro.blog/photos/…” you can replace it with “cdn.micro.blog/photos/…” and it will automatically cache the image in the content-delivery network, for faster serving around the world.
It scales the image at the provided URL to be 600 px wide. The original photo@g posted above is 1800 px wide, so adding the prefix will reduce the file size quite a lot. You can change 600x to any value that suits your needs. Or not use this at all, if you have no use for scaled down images.
My 2 cents, it’s usually a good idea to have the size be at least 2x what you expect most people to view it as, so it looks nicer on modern phone screens that are high resolution. The Micro.blog timeline currently defaults to scaling down to 1000 pixels wide. The client apps usually resize to 1800 pixels before uploading, then add a width tag of 600 making it roughly 3x the display size, but it’s not an exact science with so many different screen sizes.
Markdown render hooks were introduced in Hugo 0.62. You’re probably on Hugo 0.54. Navigate to Design and change Hugo version to 0.91. After your site has been rebuilt, your custom render hook should work. You should not have to change anything in the render hook.
The URL you’re seeing in the rendered HTML of your page is caused by the setting Use content delivery network for images (also on the Design page). The original URL for that photo is https://qrk.social/uploads/2023/840da10dce.jpg.
Thanks @sod, I was already on 0.91 and I’m still not sure if it’s working correctly or not. The resulting image is smaller than the source, but it still isn’t 600px, and my addition of loading="lazy" to the render doesn’t seem to be present either.
It’s possible that the change to using the CDN by default means that this no longer works. I believe you can turn off the CDN by going to the Design page and un-clicking “Use content delivery network for images”.
@manton does the CDN make the resizing endpoint fail?
CDN probably doesn’t have anything to do with this.
Your custom rendering hook is not running, as you’re not seeing the loading attribute. The question is why it’s not running. It’s always a challenge to troubleshoot from the outside, but here are some things to try.
Do a full rebuild of the site. Sometime, making changes to a custom theme doesn’t trigger a rebuild, and you could, in theory, be looking at old versions of your pages.
When doing the rebuild, keep an eye on the logs for any errors or hints of anything going wrong.
Make sure the right custom theme is selected on the Design page.
Double-check that the name of the template is layouts/_default/_markup/render-image.html.
If you’ve made any changes to my original template at the top of this thread, revert them.
If you have more than one blog (or a test blog) – make sure you’re doing all this on the right one.
We will figure this out, sooner or later.
Update: I just followed my own instructions in the top post with success. So at lest we know, “it works on my machine” (or Manton’s servers, rather). If there’s any comfort in that.
Unfortunately, I don’t know how to trigger a full rebuild I’m afraid. I had a look through the UI, but I can’t find an option for that. I published a test post with an image to see if it worked, wouldn’t that trigger a rebuild?
