use strict;
use warnings;

my $i = 1;    # The object number we're up to

# create object 1 somehow

open(FILE, ">", "object$i.png") or die "Failed to open object$i.png: $!";

# make sure we are writing to a binary stream
binmode FILE;

# Convert the image to PNG and print it to file
print FILE $im->png;

$i++;

# create object 2 somehow, rinse and repeat

##</code><code>##

my $filename = "object$i.jpg";
if(-e $filename) {
      die "$filename already exists in this directory\n";
      # or something more useful.
}
open(FILE, ">", $filename) or die "Failed to open $filename: $!";