Gracefulness is in the eye of the beholder. It is a rather loose term that describes a feeling that is evoked, and people might have different opinions in this regard. From a visual perspective, I feel that gracefulness is usually associated with beauty that looks natural and blends with the surroundings. It could evoke a sense of effortless strength, a lightness of being, and perhaps even quiet dignity.We find gracefulness in both the still form or in movement. The nature of the motion looks graceful to me in the following picture. An object that is not necessarily graceful in its stillness can become graceful when it begins to move. While experiencing grace in movement requires you to actually see the movement, it is possible to imagine the gracefulness of the motion from the nature of a still picture. A think a pelican gliding over the water looks graceful.This somewhat awkward looking great blue heron looks graceful to me when it begins to fly. The motion of its wings is (relatively) slow and smooth, and the bird seems to be taking flight effortlessly. But sometimes, the still image can trick you. I think the baby in the picture below, although cute, is not very graceful in its movement in real life.I have observed that still objects can look graceful from a certain visual perspective and perhaps not so much so from other points-of-view. The nature of the picture and the circumstances of the picture can enhance the feeling of gracefulness. There was a lot of construction going on around the Gateway Arch in St. Louis when we visited. Even though the arch looks stunning regardless of the surroundings,it gracefulness was truly revealed to me only from this particular point-of-view. (Like I said, gracefulness is in the eye of the beholder!)Bridges can look graceful, especially those of the suspension type. To me both the Sydney harbor bridge (which is actually a through arch bridge) and Sydney Opera House look graceful in this picture against the skyline at this time of the evening. There is something in the outlines of these structures that makes them seem even more graceful before the evening lights are turned on.Seeing more details of the structures can have a different impact on you. I think the bridge still looks graceful from this perspective.Not sure if this is still true of the opera house in this picture taken from the bridge.
I am sure there are different opinions and thoughts on this topic. There is no way to be really objective about it.