Pelican plugin that insert thumbnails along image links.

Demo page

https://chezsoi.org/lucas/blog/pages/images-libres-de-droits.html#fonts

Source Markdown: pages/images-libres-de-droits.md

Usage instructions

To enable this plugin:

1. Install the package from Pypi: pip install pelican-plugin-image-preview-thumbnailer
2. Add the plugin to your pelicanconf.py:

PLUGINS = [..., 'image_preview_thumbnailer']

3. Enable it on the article / pages you wish by inserting this piece of metadata:

Image-preview-thumbnailer: $selector

$selector is a CSS selector to target HTML elements this plugin will parse and look for <a> hyperlinks. It can be for example article if your Pelican template place your pages content in <article> tags, or just body to select the whole page. Several comma-separated values can be provided as CSS selectors to Image-preview-thumbnailer.

Supported link formats

Currently this plugin support preview of the following links:

• "raw" links to GIF/JPEG/PNG images
• links to Wikipedia/Wikimedia images
• links to ArtStation artwork pages
• links to Behance artwork pages
• links to Dafont font pages
• links to FreeSVG.org vector images
• links to Pixabay images
• links to pages with a <meta property="og:image"> or <meta property="twitter:image"> properties, like DeviantArt artworks, Flickr photos, https://itch.io pages, OpenGameArt assets or WikiArt pages

Feel free to submit PRs to add support for more image hosting websites.

Only displaying thumbnails on hover

The initial idea for this plugin was to just add 🖼️ icons after links to images, and then only display thumbnails when hovering on those icons.

To configure this plugin to behave like this, defines the following in your pelicanconf.py:

IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML = '<span class="previewable"> 🖼️</span><img src="{thumb}" class="preview-thumbnail">'

And insert those CSS rules:

                     .preview-thumbnail { display: none; }
.previewable:hover + .preview-thumbnail { display: block; }

Usage with images lazyloading

There are various Javascript libraries that can provide images lazyloading. If your Pelican template make use of one, you can customize IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML in order to benefit from it.

For example, to do so using lazysizes, defines the following in your pelicanconf.py:

IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML = '''<a href="{link}" target="_blank">
    <div class="lazyload" data-noscript=""><noscript><img src="{thumb}" alt=""></noscript></div>
</a>'''

Configuration

Available pelicanconf.py options:

• IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML (optional, default: <a href="{link}" target="_blank" class="preview-thumbnail"><img src="{thumb}" class="preview-thumbnail"></a>) : the HTML code to be inserted after every link (<a>) to an image, in order to preview it
• IMAGE_PREVIEW_THUMBNAILER_IGNORE_404 (optional, default: False) : avoid raising exceptions that abort Pelican when links are found, pointing to images, but they end up in HTTP 404 errors
• SILENT_HTTP_ERRORS (optional, default: True) : avoid raising exceptions that abort Pelican when links are found, pointing to images, but they end up with an HTTP error, of any kind. An error log message is still produced.
• IMAGE_PREVIEW_THUMBNAILER_DIR (optional, default: thumbnails) : directory where thumbnail images are stored
• IMAGE_PREVIEW_THUMBNAILER_EXCEPT_URLS (optional) : comma-separated list of regex patterns of URLs to ignore
• IMAGE_PREVIEW_THUMBNAILER_THUMB_SIZE (optional, default: 300) : size in pixel of the generated thumbnails.
• IMAGE_PREVIEW_THUMBNAILER_ENCODING (optional, default: utf-8) : encoding to use to parse HTML files
• IMAGE_PREVIEW_THUMBNAILER_HTML_PARSER (optional, default: html.parser) : parse that BEautifulSoup will use to parse HTML files
• IMAGE_PREVIEW_THUMBNAILER_CERT_VERIFY (optional, default: False) : enforce HTTPS certificates verification when sending linkbacks
• IMAGE_PREVIEW_THUMBNAILER_REQUEST_TIMEOUT (optional, in seconds, default: 3) : time in seconds allowed for each HTTP linkback request before abandon
• IMAGE_PREVIEW_THUMBNAILER_SELECTOR (optional, default: body) : CSS selector to target HTML elements this plugin will parse and look for <a> hyperlinks.
• IMAGE_PREVIEW_THUMBNAILER_USERAGENT (optional, default: pelican-plugin-image-preview-thumbnailer) : the User-Agent HTTP header to use while sending notifications.
• IMAGE_PREVIEW_THUMBNAILER (optional, default: False) : enable the plugin on all your pages

Available metadata entries:

image-preview-thumbnailer: $selector or just true
image-preview-thumbnailer-except-urls: same as IMAGE_PREVIEW_THUMBNAILER_EXCEPT_URLS
image-preview-thumbnailer-ignore-404: same as IMAGE_PREVIEW_THUMBNAILER_IGNORE_404
image-preview-thumbnailer-inserted-html: same as IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML
image-preview-thumbnailer-thumb-size: same as IMAGE_PREVIEW_THUMBNAILER_THUMB_SIZE

You will also have to define a $PIXABAY_API_KEY environment variable to download images from Pixabay.

Release notes

cf. CHANGELOG.md

Contributing

Contributions are welcome and much appreciated. Every little bit helps. You can contribute by improving the documentation, adding missing features, and fixing bugs. You can also help out by reviewing and commenting on existing issues.

To start contributing to this plugin, review the Contributing to Pelican documentation, beginning with the Contributing Code section.

Releasing a new version

With a valid ~/.pypirc:

1. update CHANGELOG.md
2. bump version in pyproject.toml
3. poetry build && poetry publish
4. perform a release on GitGub, including the description added to CHANGELOG.md

Linter & tests

To execute them:

pylint *.py
pytest