Is there an easy way to align / position / size reference images displayed in the viewport?

The documentation states that Image Planes should be used for displaying reference images as backgrounds - but I can't seem to find a way to position these easily.

In the positioning attribute of the Image Plane you can adjust the X,Y,Z and the Width and Height of the loaded image, but its very difficult positioning the image plane correctly in the viewport by entering these values manually.

I was using XSI before, and using the Rotoscopy function I could display an image in the viewport and use the usual translate tools to position the image, and then 'lock' the viewport so scaling of the grid would be locked to the image scaling.

Is there a way to do something similar with Maya?