You'll never get precise dimensions from a photo, but you can get quite close. Generally, a photographer can minimize distortion by photographing a bike straight-on from the side (film plane of the camera exactly parallel to the longitudinal plane of the bike) using a long telephoto lens. In the case of the Schwinn World track bike photo above, you can tell that's what the photographer did since the non-driveside seat stay and chain stay as well as the non-driveside fork blade are all pretty well hidden by the driveside stays and fork blade.

I use a Gerber variable scale which I set to a known length on the 1899 Schwinn World Model 33 photo, in this case the 24" c-t seat tube length. I then did a sanity check with scale my looking at the BB drop (3") and head tube length (6 1/2") to ensure they all jived. Looking at the dimensions of the front and rear wheel rim vertical and horizontal inside diameters, you can see the front wheel was closer to the camera than the rear wheel as the front rim is slightly larger. Also, the camera was positioned slightly above the vertical center of the frame as the pedals and the handlebar appear to be photographed from above, and this is why the vertical rim diameters are slightly less than the horizontal rim diameters of both wheels. This requires some judicious averaging to get more accurate measurements.

Here's the catalog page.


Here's the 24" seat tube scaled.


Bottom Bracket Drop.


Head Tube Length.


Fork Rake.


Top Tube Length.


Crank Arm Length.