ADDBORDER draws a border around an image.
NEWIMG = ADDBORDER(IMG, T, C, S) adds a border to the image IMG with thickness T, in pixels. C specifies the color, and should match the color format of the image (e.g., RGB or indexed). STROKE is a string indicating the position of the border:
'inner' - border is added to the inside of the image. The dimensions of OUT will be the same as IMG.
'outer' - the border sits completely outside of the image, and does not obscure any portion of it.
'center' - the border straddles the edges of the image.
X2 = addborder(X, 20, 62, 'center');