If you want to extend an ImageMagick script with Perl, you need to see Perl Magick page
You can see how simple the commands are, and no one I know of yet, has codified them into the Wx framework.
For examples of what you can do with Tk, see Tk and ImageMagick . If you want an example of making sliders in Tk, to set your PerlMagick options, see SuperFormula with gnuplot and Tk.
All you need to do is learn how to rebuild the image and re-display it, then setup some sliders and spin boxes to set your PerlMagick options.