If there's anything I've learned from tutorials on this site and Makerbot Thingiverse (which also provided great test patterns - I highly recommend the Moebius Strip
piece as a calibration and material test cut), it's that prepping complicated artwork for vector cutting is a pain. Rastering, not so much - turning an image black-and-white (or multi-colored for different cut paths or depths) is easy enough, and well-covered in Photoshop tutorials on silhouetting.
But vectors...so, so easy for aircraft parts, but so annoying for jagged edges. The rudder plate shown here was directly exported from Pro/ENGINEER (my go-to CAD modeler - yes, I prefer its overly complex GUI to Solidworks, Inventor, Sketchup, whathaveyou...I've used it for everything from designing RC aircraft to outdoor storage sheds with full Mechanica stress analyses), and only contains vector pathlines by default - that's the one great thing about DXF (Drawing Exchange Format - AutoCAD's vector plotting format). But a jagged or wrinkly edge like in my fern? Needs some pre-process loving and careful manipulation to get an optimum path.
Too bad I didn't know any of that going in - the fern was my first fully-custom cut pattern, so after Google searches and reading a few tutorials, I did what I always do...brute force trial-and-error. Not always the best method, admittedly, but hey, I'm an engineer. It's not like I've spent seven years of my life learning how to approach problems elegantly...
So! To get this file running as quickly as possible (since I'd thought students would want cuts before Spring Break...I was optimistic by three weeks), I did some simple photo manipulation using my favorite starting program, Paint.net. Not as powerful as GIMP or Photoshop, but I'm not a fan of the former's poorly-customizable plugins or the latter's price, and Paint.net is more than sufficient to get to the next program (Inkscape). My first step was to cut a single board out of the picture and size it to the wood template I'd be laser cutting (24" x 12" x 1/8" birch plywood). This had two side benefits - first, I wouldn't have to deal with vector scaling in Inkscape (well it's very accurate, it's too easy to miss a single node and screw up your image), and second, it filtered out unnecessary details. This wouldn't usually be a good thing, but for this image it magnified the shadows on the wall, which were better representations of the fern's wiggly edges.
It also allowed me to rapidly size the leaf to its proper laser cut board size, by scaling and using black-space to approximate the full leaf size (seen in the intro step). Naturally, this was overlooked when I took the file to the cutter and overscaled...since I'd forgotten to bring the JPG of the original leaf with me to my control computer...so my final piece (the left-hand leaf) was almost 30% too large...go figure. But hey, I never said this would be a perfect recreation. The other two boards came out true-to-life after more careful scaling.