I also use d20pro and a projector and I started preparing to run Jade Regent.
1) Use Adobe reader and copy the image from the PDF. You will get the best quality that way. If you can, use the map PDF subscribers get. You can hide secrets and room numbers. Starting wit JR-2 you can even remove the grid. If you use that you may have to use a screen shut of the scaled up map instead of copying do. You can export another image with secrets and such.
2) Paste or open the image in an image editing app such as Photoshop. Do any cleanup you may have to do. Remove Rome numbers and secrets if you don't have access to the map PDF. Put secrets and such on another layer.
3) Make a grid on a layer with a regular width such as 50 pixels then try scaling you image layer to get as close to it as possible. You may have to do non square scaling such as 102% by 107%.
4) Save your image as a PNG or JPG with or without your grid layer depending on what look better. I personally remove the grid completely. I use d20pro grid instead.
5) Load your map in d20pro and scale it to a grid fitting your grid layer you did before. Adjust the positioning to fit your map.
6) Create fake creatures with images of your secret rooms (just crop the main image export with secrets cropped around the right part of the map.) and place them on the map with the invisible flag.
7) Place fog of war squares every ware the Party can't see.
Voila !
I also prepare all enemies in Hero Lab and import them then place then on th map at their location. It makes it really easy to check for adds to encounter if the party in to noisy or someone do something stupid ;)
