I tend to go the png -> svg route as well. Usually i use pngtosvg.com and play with the settings there until i get it close to what i want. You could also use Vector Magic but you have to pay for that service.
When i import the svg into easel, i always have to do some cleanup. For instance I used your picture:
Came up with this svg:
and imported it into easel.
There are a lot of artifacts around the edges. To clean this up i made a duplicate workpiece, set all shapes in that workpiece to the same depth, combined them, then offset the single shape by a few thou to “absorb” the artifacts.
At this point i would go through and copy different shapes from the original work piece and paste them on the new workpiece. to get that detail back. You may also need to do use the “edit points” feature to make tweaks to the shapes.
You could also use this: http://drububu.com/tutorial/bitmap-to-vector.html
to create a pixel-perfect svg for the png you started with. However, when you import into easel you are going to get a lot of individual shapes. You can use the “select by matching depth” and combine them together, but you’ll havve to find a way to smooth out the shape for carving.
Good luck on whatever path you choose! let us know how it turns out