Lunatrap - aha - as documented...
[quote:15npgv87]High quality: mipmaps are enabled and the spritesheet after export pads out all images to power-of-two sizes. This can significantly increase memory use, but can resolve light fringing that can sometimes occur along the borders of downscaled objects in medium quality mode. Do not use this mode unless fringing is observed, since it can use a lot more memory.
You have deliberately chosen an export mode that is documented as using more memory. Unless you see the fringing artefacts, set it to medium and the memory use should go down.