At work I'm reduced to using MS Paint; at home I'm strictly a Paint Shop Pro man! However, both have the same function as your Mac Preview. The issue is that all 3 shuttlecraft pictured seem to have a half-pixel or so at either end, which in fact they would need to avoid being quite so blunt fore & aft (as per the miniature). This is problem when using images at such low resolution, but a variance of +/-1% is hardly a deal breaker. Very true (and I think you made a typo there!) but I avoid using decimals in the imperial measuring system - it makes for some unwieldy posts! Depends on which you lay more credence to, the intention of the creators or what actually ended up on our TV screens. If you prefer the former I strongly reccommend checking out Shaw's thread here. His goal was to create a set of internal plans consistent with Matt Jefferies' original designs and intentions and there's a lot of good work there.