Hi BVS,
For increasing the size of the image, there are 2 steps. If you select the sizing option "Stretch Image", the image will expand to fill the size of the picture box. Then, to increase its size, drag on the square at corner of the picture box to the size you would like. Or alternatively, you can set the width & height of the picture box by modifying those properties in the property grid:
After this, you can change the alignment of the image. This can be done by dragging the picture box, or modifying the X & Y properties (see the above image).
Regarding nothing happening when you click print preview, the PDF should open in a new window. Can you check to make sure your browser isn't blocking pop ups? If this doesn't work, could you try in another browser or on another computer? Have you been able to print preview before? Can you also let us know what browser and version you are using?
-Russell