Illustrations that I have added to Wikimedia Commons and inserted in some articles:
Illustration of the electric field surrounding a positive (red) and a negative (green) charge (click for larger image). I inserted this illustration in the Electric field article.
Illustration of the electric field surrounding two equal charges (click for larger image).
Illustration of the electric field surrounding one positive charge (click for larger image). I'm not quite satisfied with this one, but I don't see any article where it would be obvious to use, so I won't improve it just now.
If you have a scroll wheel mouse, hold down the Ctrl key on the keyboard while you roll the scroll wheel—it makes the text larger or smaller instantly!
Bonus tip: This tip works in many other applications too! For example, it is generally used for zooming in Microsoft Windows.