@Kermet, thanks for the link. That helped me solved what the real issue was. It’s not counting the images in the post as attachments. When you insert an image into a post, it adds it to that posts’ media gallery. The post I was testing this on was only showing one image in it’s media gallery even after I attached more images. Other posts with more images in their media gallery are showing more images.
I use attachments plugin (http://wordpress.org/extend/plugins/attachments/) to attach media to a post, then i can retrieve all the attached media as an array.
You could try that if wordpress’ get_attachment function doesn’t do the trick for you