I just loved the lighting on the water and rocks. That's what makes Yosemite falls so beautiful for me. It is not the tallest waterfall I have seen. But definitely one of the most beautiful, simply because it is so well protected by the flora of Yosemite park.
Best season to visit Yosemite National Park is Early May to Early June which is the beginning of high season. The prices are not peak and yet the park is beautiful with the recently melted snow.
Worst time of the year to visit Yosemite National Park is 4th of July weekend and July-August. The prices are at peak, park is loaded with tourists and campers with kids; it looks more like Disney Land rather than a national Park.
This is just the last third of the waterfall. Yosemite waterfall falls in 3 steps, top leg, middle tier and bottom third. (leg, tier and third are my terms., they are all unequal thirds of the falls... confused in Math :O )