Resize image to make an avatar
• 205 words • 1 min
Problem statement: Given a .png image suitable to be used as a profile
picture (an avatar in a forum, for example), convert it to 80x80, ensure its
file size is under 10KiB and keep its transparency when existing. The extension
should remain .png.
This kind of task is perfect for the LLM™. It took me a few round-trip prompts to achieve the desired outcome:
% magick image.png -resize 80x80 -fuzz 10% -transparent white
% pngquant --quality=70-85 --force --output image.pngmagick comes from ImageMagick. Most
likely you already have it installed if you’re in Linux or macOS.
Fun fact: the command used to be called convert (it is still in my muscle
memory!) but not in newer versions of ImageMagick:
% convert
WARNING: The convert command is deprecated in IMv7, use "magick" instead of "convert" or "magick convert"
[...]pngquant is new to me:
pngquant is a command-line utility and a library for lossy compression of PNG images.
The conversion reduces file sizes significantly (often as much as 70%) and preserves full alpha transparency. Generated images are compatible with all web browsers and operating systems.
In my little experiment:
- input: 52KB, 256 x 256 pixels
- output: 4.1KB, 80 x 80 pixels, with transparent background
