Here is a fun chart for a fun technique.
This portrait is created by switching from knit st to purl, and is suitable for beginners too.

Need to know: knit, purl and how to read charts.
Bonus material: how to mount and frame the picture.

Gauge and yarn are not specified, but it is best done with plain light color yarn. The picture is done in one color and 2 skeins of medium/thin yarn (500 yards or so) should be enough, but make sure they are of the same dye lot.