> When you use xcc mixer to resize RA2 infantry to TS infantry size, the mixer 'demolishes' half of the unit's body, leaving purple dots around the unit. Why does this happen,

It has to do with alpha scaling. Which version of XCC Mixer did you use?

> is there an alternative to this that wont demolish perfectly good infantry. Ive tried convertin the shp's to pcx and resizing them on PSP manually but it is too time consuming for infantry.

You could try Image Robot.