How to clear a picture...?

[TotallyConfused]

Ohk, first off i feel stupid for even posting this, im not quite sure this is even the right place to post it but i need help, im only in a programming 1 class in high school but we are doing our final projects and me and my partner chose Battleship.
Question is,
We are using a 2D Array of picture boxes, after i click the picture boxes and decide to runa new game, the pictures don't clear only the background,How do i make the pictures dissapear? this is what i have

For x = 0 To 9
For y = 0 To 9
*I NEED SOMETHING HERE TO CLEAR PICTURES*
mirrorboard(x, y) = ""
board(x, y).BackColor = Color.Transparent
Next
Next

I just nead a piece of code that will clear the picture box's image. And i have no idea how to do that.

Any help would be appreciated, and im sorrry for the newbie question.

Thanks.

 

[JohnH]

pictureboxes(x, y).Image = Nothing