If I was asking ya question I would look to see what V6 high rez map size is

DAZ Split maps. so if her face was ???x??? and her body was  ???x??? then I guess that's the 2014 standard.

photoshop 2014 can convert a simple 2D pic in to a simple 2D normal maps & bump maps .

if you want to make killer complicated normal maps & Vector maps & old faithful Displacement Maps. zBrush can do it all & I think Mudbox,Blender can also.

 these are fun also for different stuff.

 http://quixel.se/

 http://www.allegorithmic.com/

 http://3d-coat.com/

for uv texturing http://pixologic.com/zclassroom/homeroom/#texturing

they even have a zBrush GoZ photoshop video

ya can use gimp to make the .jpgs for zBrush spot light

I think ya can get photoshop & mudbox for around $10.00 a month each.

don't think I've paid for a zBrush up grade since zBrush 1.55b
Think to go to 64 bit zBrush 5 it's a cost.

Blender ,Gimp is free.

on my PC 
for gimp 3000x3000 is about as large as I go with out lag.
photoshop 2014 is fast enough for me to go 8192 x 8192.

 

 

 

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The Artist that will fight for decades to conquer their media.
Even if you never know their name ,your know their Art.
Dark Sphere Mage Vengeance