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PNGquant 2.2.0
av Christian Krause
Komprimerar PNG-bilagor och infogade bilder med libimagequant (WASM) och frågar om bekräftelse innan sändning.
Om detta tillägg
There are several Thunderbird add-ons that resize attached images. None of them met my requirements—at all.
Many of these projects indiscriminately reduce the dimensions of attached images—when it comes to screenshots, this usually results in poor readability. In addition, some of them only process attachments and ignore inline images altogether. PNG files are often not supported at all, or are blindly converted to JPG, causing existing alpha channels to be lost and leaving images with a white background instead of transparency. On top of that, they frequently rely on simple downsizing algorithms (bicubic, bilinear) that introduce visible quality loss.
In short: the results are insufficient for most use cases, and in the worst cases the images become unusable after conversion.
I am well aware of the processing steps required to minimize image file size: determining the appropriate target resolution and format, reducing colors using pngquant and fine-tuning with oxipng, or compressing JPG images using jpegli. Finally, the optimized image needs to be reattached to the email. For saving 50 KB, this effort is hardly worth it. And yet, over the course of a year, this adds up to hundreds of megabytes of unnecessarily large images per mailbox—affecting both sender and recipient alike. They clutter inboxes and backup storage, and are needlessly transmitted over the network, even though 70–80% savings are almost always achievable without visible quality loss.
My goal was to build an add-on that integrates state-of-the-art image compression tools, tests both the JPEG and PNG pipelines, and retains the smallest resulting file. The user defines the desired quality level via compression templates, and the add-on ensures that file size is reduced to the technically achievable minimum while preserving that quality.
When images are resized, high-quality downscaling algorithms are used, delivering significantly better results than the commonly used, browser-native approaches.
Here it is: probably the best image compression add-on for Thunderbird.
- State-of-the-art compression algorithms such as JPEGli, pngquant, and oxipng, integrated as WASM libraries.
- Saves 70–80% of storage space, even without optional resizing.
- Converts PNG files to JPG when doing so saves space.
- Resizes images to their HTML inline dimensions.
- Uses different resizing algorithms, optimized for PNGs (Mitchell) or typical JPG images (Lanczos).
- Create, import, and export compression profiles, then automatically apply them to specific image types (quoted images, inline images, or attachments)—or apply them manually to individual images.
- Compress, undo, redo, and adjust templates—improve your own workflow and deepen your understanding of image compression through direct comparisons.
- Remove images from quoted content entirely.
- Permanently exclude images from the workflow—for example, your own email signature.
- Download compressed images directly from the application. This lets you build other compression workflows around the add-on that are unrelated to email—for example, website optimization.
- Available in 9 languages.
Many of these projects indiscriminately reduce the dimensions of attached images—when it comes to screenshots, this usually results in poor readability. In addition, some of them only process attachments and ignore inline images altogether. PNG files are often not supported at all, or are blindly converted to JPG, causing existing alpha channels to be lost and leaving images with a white background instead of transparency. On top of that, they frequently rely on simple downsizing algorithms (bicubic, bilinear) that introduce visible quality loss.
In short: the results are insufficient for most use cases, and in the worst cases the images become unusable after conversion.
I am well aware of the processing steps required to minimize image file size: determining the appropriate target resolution and format, reducing colors using pngquant and fine-tuning with oxipng, or compressing JPG images using jpegli. Finally, the optimized image needs to be reattached to the email. For saving 50 KB, this effort is hardly worth it. And yet, over the course of a year, this adds up to hundreds of megabytes of unnecessarily large images per mailbox—affecting both sender and recipient alike. They clutter inboxes and backup storage, and are needlessly transmitted over the network, even though 70–80% savings are almost always achievable without visible quality loss.
My goal was to build an add-on that integrates state-of-the-art image compression tools, tests both the JPEG and PNG pipelines, and retains the smallest resulting file. The user defines the desired quality level via compression templates, and the add-on ensures that file size is reduced to the technically achievable minimum while preserving that quality.
When images are resized, high-quality downscaling algorithms are used, delivering significantly better results than the commonly used, browser-native approaches.
Here it is: probably the best image compression add-on for Thunderbird.
- State-of-the-art compression algorithms such as JPEGli, pngquant, and oxipng, integrated as WASM libraries.
- Saves 70–80% of storage space, even without optional resizing.
- Converts PNG files to JPG when doing so saves space.
- Resizes images to their HTML inline dimensions.
- Uses different resizing algorithms, optimized for PNGs (Mitchell) or typical JPG images (Lanczos).
- Create, import, and export compression profiles, then automatically apply them to specific image types (quoted images, inline images, or attachments)—or apply them manually to individual images.
- Compress, undo, redo, and adjust templates—improve your own workflow and deepen your understanding of image compression through direct comparisons.
- Remove images from quoted content entirely.
- Permanently exclude images from the workflow—for example, your own email signature.
- Download compressed images directly from the application. This lets you build other compression workflows around the add-on that are unrelated to email—for example, website optimization.
- Available in 9 languages.
