Scaling Down Images in GIMP
During the making of this website I tried to scale down an image of 500 by 500 pixels to the size of 32 by 32 pixels. Scaling the image down using the GIMP's image-scaling feature did not work so well.
This is what the image (a dark circle on white background) looks like, when you use the GIMP's "Image" -> "Scale Image…" function and reduce the image size from 500 to 32 pixels:
Scaled from 500px to 32px directly.
It's barely noticeable but the once perfectly round circle now seems miss something on the right and bottom.
What I found out is that - in order to prevent this effect - you need to scale up the image first. I used 640 (twenty times 32) as the intermediate size.
Scaled 500px to 640px to 32px.
Voilà: A perfect circle.