First post I can remember on gantry-crane - as per above, I also can't see image.
Mine is an "H" configuration. I consists of three sections of barn-door hangers/cars from Grainger - one over the headstock, and one over the end - both at ninety-degrees to the axis. If you're lifting logs 100+ lbs, reinforced the ceiling joists is a good idea. The hanger going across is also reinforced - hanging from it's car is a chain-hoist from Harbor Freight.
I use a heavy chain around the log to mount - I then use a sling after it's shaped.
I can lift a 400-lb log no problem. If I get the axis wrong, and I frequently do, I can easily reposition. If a radial-grain, I turn the tenon at the live-center end and then attach the faceplate while suspended on the chain-hoist. Same with axial grain except I turn a dove-tail tenon and then mount the steady-rest.
The outboard end uses a I-beam going down the center-line - it is suspended from the ceiling with metal plates on the floor above. The car for the I-beam was from Harbor Freight - cost about $60 and I use the same chain-hoist. No problem with a 1000-lb+ (used with Planet Mesquire)/
A crane/hoist system is not an option for heavy logs. I noticed my neighbors ducking inside when I walked out with that "hey buddy-pal - got a minute" look on my face.