The 'makeImage' subroutine is acting like a function, and not a method.

I find it easiest to understand the difference between a function and a method by looking at it in the way that perl actually handles them.

# function call
grizzly::makeImage();

# class method call
grizzly->makeImage();
# Which perl translates to
grizzly::makeImage('grizzly');

# object method call
$nub->makeImage();
# which perl translates to
grizzly::makeImage($nub);
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So unless 'makeImage' is expecting the classname or the object itself as the first parameter, it will only work as a function. I would recommend that you read the perltoot docs that come with perl. It will give you much better insight into how objects work in perl that I can in this post.