How to increase the resoultion of an PNG image

[vinumanikandan]

Hi I'M using Perl GD to create an image with response to user entry and the database retrevial using the Perl GD and DBI and CGI modules. Even though i'm successful in making the png image my boss is not happy at the resoultion of the image. The code is as in below

my $im = new GD::Image(710,$Image_Height);
my $white = $im->colorAllocate(255,255,255);
my $black = $im->colorAllocate(0,0,0);       
my $blue = $im->colorAllocate(0,0,255);
$im->transparent($white);
$im->interlaced('true');

$im->filledRectangle($Trans_X1,$Image_Height-20,$Trans_X1,$Image_Heigh
+t-10,$scale_line); ### Scale ######
    $im->filledRectangle($Trans_X1+$Scale_Length,$Image_Height-20,$Tra
+ns_X1+$Scale_Length,$Image_Height-10,$scale_line); ### Scale ######

    $im->string(gdSmallFont,$Trans_X1,$Image_Height-32,1,$scale_line);
    $im->string(gdSmallFont,$Trans_X1+$Scale_Length,$Image_Height-32,$
+Length,$scale_line);
    

    open OUT,">$ID.png";
    binmode OUT;
    # Convert the image to PNG and print it on standard output
    print OUT $im->png;
    close OUT;

Please let me know what to do to increase the resoultion of the image (above is psuedo code)