Above, the initial image (a) is distorted by making the four corners (blue dots) move to the new positions marked by the four red circles. PerspecX allows you to specify a "perspective strength" for the transformation, and the images (b) and (c) show the results of using low and high values for this parameter.
The two image transformations above show how PerspecX can distort from "plan view" to "oblique view" or vice versa.
(a), (b) and (c) above are magnified portions of fine lines in an image after perspective distortions with PerspecX. (a) is the "raw" image produced without enhancement. (b) and (c) show the effects of increasing levels of anti-aliasing/super-sampling/scaling during the transformation.
An entertaining alternative to perspective warping is to turn your image into a "fractal". The above pair of images are before and after using the PerspecX "Fractalize" command. Click on the right hand image to see it full size - this image is 85 Kbytes,so may take a little while to download.