Use Deep Focus to visualize an entire image stack in a single plane (Maximum / Minimum intensity projection for another method).
The program collapses the focus information from the 3D image onto a single image plane; it creates a new image and places it at the Z-depth of the top of the stack.
Deep focus is a method that identifies the pixels with the highest sharpness value, while minimum/maximum projection identifies the maximum (or the minimum) intensity value of each pixel along the z axis is projected onto the 2D plane.