In simple terms it is a square image which represents a user on an internet site.
One Instructables member was asking for contributions and I thought I'd have a go for something to do on a Bank-holiday weekend.
Step 1: Theme
The member seems to like K'NEX, and there's some kind of "Jam" element, evidenced at least by the Forum Topic.
I thought of "K'NEX jam"
Step 2: Tools and Materials
A clean and empty jam-jar
Some blackcurrant juice drink
A digital camera
Step 3: The Subject
Pieces of K'NEX were arranged in the jam-jar, with thought for colour-balance and general aesthetics. I did not just toss K'NEX in a jar. (OK I did just toss K'NEX in the jar, but it didn't look good so I tipped it out and started again)
To create a jam-like effect, I simply filled the jar with juice-drink.
Step 4: Photography
A basic light box was assembled from, a box. Placed in a well-lit area the white interior served well enough.
The jam-jar was placed on a plinth (double-sided sticky-foam tape) to lift from the base with a view to making the final image clean-up easier.
I took eight shots of the jar, from various angles, either without flash or with slow-shutter flash. This gave me a choice - some were better than others and I've posted all of them only to show the value in having a selection.
Step 5: Image Manipulation
First, Image>Adjust>Auto Levels.
This makes the colour balance nicer, and the white whiter.
The R channel was moved to 2
The G channel to 1.2
The B channel to 1.4
This made the image brighter and more colourful, with an emphasis towards jammy-red.
Third, a bit of painting with a white paintbrush, removed the box background. The box being white-ish in the first place made this very easy.
Step 6: Finishing
Within Instructables all avatars are displayed as 48x48 squares, if your image isn't square it will be cropped - meaning bits will be cut off it to make it square.
Pasting into MS Paint (I just find it easier) I just needed to check Image>Attributes and adjust them to be square (400x400)
(Although the rules said "Deadline for entries: 2009-04-12 11:59 PM PST" entries for Burning Questions Round 7 had already closed by the time I published this)