When You Repeat a Background Image, Is Specifying Position Necessary?

I'm a little confused about something.

When you repeat an image horizontally or vertically, is it necessary to specify the image's starting position? In other words, is this sufficient:

#main_div {
background: #fff url('image.jpg') repeat-y;
}

Code (markup):

Or must I include the starting position of the image, thus:

#main_div {
background: #fff url('image.jpg') repeat-y center top;
}

Code (markup):

 

I have coded a lot of designs and there wasn't a case then I needed to do this so I think it isn't necessary to specify starting position.

 

When in doubt, RTFM.

cheers,

gary

 

No, Specifying the background position is not mandatory. It is optional. If nothing is mentioned. By default it is top left.