The functions are:
`function printAlbumMap($zoomlevel='8', $type=NULL, $width=NULL, $height=NULL)`
`function printImageMap($zoomlevel='6', $type=NULL, $width=NULL, $height=NULL))`
So, it would appear (looking at the code) that you can pass the width and height dimensions as the third and fourth parameters. When these parameters are not passed, the code leaves the defaults as they were which should be 595 x 300.
So, it would seem that if you do not pass any parameters to these print functions, you would get a map that is 595 x 300 (as in your image map.)
I also looked for calls on these functions in the distributed themes. The only themes calling printAlbumMap are Effervescence+ and Example, which do not pass parameters for width and height. Which theme are you using?