Geysir is the geyser from which all geysers get their name. It used to erupt 100m into the air, now it doesn't erupt at all. Here's a picture from July 2015:
Nearby Strokkur, though, still erupts every 6 minutes or so. It's more like an explosion than a fountain, and the water is spit about 100 feet into the air. Here's a 2015 summer shot of Strokkur, with a crowd waiting to see the big event. Notice all the greenery!
I didn't take pictures this trip but I got some good video, which I spliced together (editing out all the waiting) and put on Vimeo. You'll see Strokkur erupt from a distance, then up close, and then in slow motion. Notice all the whitery!