Here's a size comparison of several snowdrops blooming now.
The common snowdrop, Galanthus nivalis, is not in bloom yet, so a direct, side-by-side comparison in size between it and these very robust sorts cannot be shown. So I've done the best I can with what's available: I've included a budded scape of Galanthus nivalis and have used a stem of Galanthus 'S. Arnott' for comparison. 'S. Arnott' itself is a significant jump in size over the common snowdrop, and I hope this helps to give an idea of the size of these big ones.
The remaining ones are all forms of Galanthus elwesii in the broad sense, and it's not hard to see why a half-century ago Galanthus elwesii was marketed as The Giant Snowdrop. There was in fact a company which called itself The Giant Snowdrop Company back then. The Giant Snowdrop Company is long gone, but its spirit (and possibly some of its plants) has been revived here:
Now back to the plants shown above. From left to right they are 'S. Arnott', then four progressively larger forms of Galanthus elwesii and finally on the right the budded scape of the common snowdrop, Galanthus nivalis.
The image which follows was added on February 7, 2012, and shows the contrast in size between the small common snowdrop, Galanthus nivalis, and one of my big ones.