Panning can be done by clicking the MMB and dragging.
Zooming can be done by scrolling Wheel up or down. Also, as in the 3D View, you can use NumpadPlus or NumpadMinus to zoom.
Also see Navigating in the Image editor.
- UV Local View
- Displays only the UV faces that are assigned to the currently displayed image.
- Display Other Objects
- Displays the UVs of selected objects (Object Mode) in the background.
- Display Texture Paint UVs
- Hides the UVs in Paint Mode.
- Frame Selected
- Change view so that all selected uv vertices are visible.