Hi
For a simple zoom or pan, right click your image on the sequence line to select and then the yellow star at the left end.
Click the small down arrow next to "Add Effects" tab and choose CROP.
You will now see a preview window to the right and a thumbnail with an orange rectangle on the left. Ther will also be the keyframe block to the right of the green crosses as mentioned by Borate.
You can force the aspect ratio to 4:3 or 16:9 as you wish or leave it free. It is best to force a particular ratio (usually 16:9) as if you use "None" the effect will leave black bars in the sequence line image. 16:9 will ensure that the VP is always full.
Make sure that the red cursor line is at the left (start of the image clip) although you can start your effect at any place.
Drag the sides or corners of the orange rectangle and drag it about to outline the starting frame of your effect. You will see the blue lines in the keyframe panels move up or down.
When you are happy click the green cross. This will place orange blocks on the blue line to mark the parameters for your first keyframe.
Now move the red cursor bar to the end point for your effect. The orange blocks will turn green showing the keyframe has been recorded.
Now alter your orange rectangle to reflect the end image frame for your effect. You will see the blue lines move again but they will remain fixed at the green blocks.
When you are happy with the end framing move the cursor bar again to fix the end keyframe. You can review your effect on the right.
Close the "Applied Effects" window and wait a moment for VP to create the effect.
The speed of the effect depends on the duration of the particular image. This can be varied most easily in storyboard mode.
You can create any number of keyframes throughout the image clip to produce more complex movements of the frame size.
If you just want to pan the image then the start and final rectangle (obviously samller than the actual image) should be at the same height in both keyframes.
Nat