Look where it say's "width:200px;height:120px. you can change the number. Obviously, bigger numbers make it bigger, smaller number's make it smaller.
Border-width is how thick the border is. it can be 1px, 2px, 3px, 4px, ect.
color:000000 -- that's the color of the border. if you need help with the color you want look at hex color codes and choose one.
border-style:dashed. The border can be:
Dotted
Solid
Dashed
Double
Groove
Ridge
Inset
Outset
That's a simple blog.
For a more complex blog:
background="http://www.snowcrest.net/cafemocha/images/Purple%20Pink%20Dots%20Background.gif" -- that's where the image comes from. Take a url and put it inbetween the " "
adjust the width and hieght of the outer border to match the picture.
table width="230" height="216" background="http://www.snowcrest.net/cafemocha/images/Purple%20Pink%20Dots%20Background.gif" border="0"
This measures starting from the top td height="33" change where it says "33"
That's how to add a picture to your blog.