Open Thinkering


Tag: compression

HOWTO: Create radically smaller images for your minimalist blog

Inspired by Low-tech magazine’s solar powered website, I searched the web to find out how to create a ‘stippled’ effect for images. This reduced the size of an 2.2MB image to a mere 30.6KB, which if I’m not mistaken, is a reduction in filesize of over 95%! Here’s how to do it, using free and open source software.


0. Download and install GIMP (GNU Image Manipulation Program)

1. Open the image you want to convert in GIMP

2. Resize the image to the maximum width of your blog (~600px in my case) by going to the Image menu and then to ‘Scale Image…’

3. Convert the image to greyscale by going back to the Image menu then Mode and selecting ‘Greyscale’

(optional step: wash out the image by going to the Colours menu then Levels and change the number in the box under ‘Output levels’ to 180)

4. Convert the image to indexed colours by again going to the Image menu then Mode and this time selecting ‘Indexed…’

In the box that appears:

  • Under Colourmap choose ‘Use black and white (1-bit) palette’
  • Ensure box ‘Remove unused and duplicate colours from colourmap’ is checked
  • From the drop-down Colour dithering option choose ‘Floyd-Steinberg (normal)’
  • Press the Convert button

5. Export the image by going to the File menu and selecting ‘Export As…’ In the box that appears, type in a filename that ends in ‘png’ (e.g. image.png)

This post is Day 16 of my #100DaysToOffload challenge. Want to get involved? Find out more at