I need to know the width and height of an image to set a imageView depending on whether a picture is portrait or landscape.

I've taken a look at image_view_scaling.js and the following works

var imageView1 = Titanium.UI.createImageView({
    url:'http://www.appcelerator.com/wp-content/uploads/2009/06/titanium_desk.png',
    width: 'auto',
    height: 'auto',
});
view1.add(imageView1)

var blob = imageView1.toBlob();
alert(blob.width + "x" + blob.height);

The problem is that my images are local and I'm therefor using a 'file'. The following code…

var fileImage = Ti.Filesystem.getFile(Titanium.Filesystem.resourcesDirectory, win.objProp1[win.galleryNumber].photos[0]);

var imageView1 = Titanium.UI.createImageView({
    image:fileImage,
    width: 'auto',
    height: 'auto',
});
view1.add(imageView1)

var blob = imageView1.toBlob();
alert(blob.width + "x" + blob.height);

Generates this error

While executing Timer, received script error. 'Result of expression 'blob' [null] is not an object.

Any ideas what's wrong?