Power of two tileset export

Hey there
Would it be possible to have the tileset export to a power of two size? This would be best for when importing to Unity etc as it helps improve performance and things.
At the moment my tiles are 32x32 and my tileset is 8 tiles wide and 10 tall. On export this results in an image that is 256x320, this is non power of two an so unoptimised. I'm currently editing the image to extend the canvas up to 512 tall so that it fits power of two. Could this be added as an option?
Thanks and keep up the great work!
Comments
As Hamenopi said, I think the best way is to simply make the canvas the size you need on export, unless I misunderstand the problem.