Draws the outline of a rectangle, to this Image.
.drawRect( x, y, width, height, isCentred=false )
Draws the outline of a rectangle. The x/y location refers to either the top-left corner, or the middle, depending on if 'isCentred' is false or true. The 'width' and 'height' are the total size of the rectangle.
.drawRect( x, y, width, height, xAlign, yAlign )
Draws a rectangle outline, but also provides x and y alignment options. See the article on How Alignment Works for more information.