I don't know about Illustrator, or whether you need to extract or convert the images.

You might try the efficient "ping" method of Image::Magick, if you can get at the image.

#!/usr/bin/perl -w
use Image::Magick;

my $x = $ARGV[0];
my $image;
$image = Image::Magick->new;
$image->Read($x);
my ($w,$h)= $image->Get('columns','height');
print $x,' is ',$w.'x'.$h,"\n";
#this is very inneficient memory wise, use Ping

($width, $height, $size, $format) = $image->Ping($x); 
print $width,"\n", $height,"\n" ,$size,"\n", $format,"\n";
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OR Image::Size

#!/usr/bin/perl
use strict;
use warnings;
use LWP::Simple;
use Image::Size;

my $url = 'YOUR URL HERE';
my $img = get($url);

my ($width, $height) = imgsize(\$img);
print "$url is ${width}x${height}\n";
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