Your picture didn't upload. Cannot be more than 100k in size. The Vitus is pretty distinctive - it is completely aluminum, vertical rear dropouts, glued and riveted brake bridge. Earlier ones have cable guides for the rear brake cable glued to the top tube, while later ones have internal cable routing for the rear brake cable. The lugs are aluminum and the frame tubing fits the lug nearly perfectly (same outer diameter). The frames were normally anodized one of many colors, but if the bike has seen a lot of sun it may have returned to silver. The bottom bracket should be marked "brevetta Vitus...etc" in a box on the bottom bracket. On the left side of the steerer tube a number will be cast inside of a circle - that is the frame size in centimeters. A very nice bicycle - I'd like to say I rode mine today, but I worked through lunch.

And if it isn't a Vitus, then what is it? give posting pictures another try...