The photo slideshows are actually hosted on Picasaweb, which is owned and managed by Google.
The high speed at which the pictures move is due to the default speed of 3 seconds per slide. Some slideshows start running immediately, while others require you to click the triangle in the circle in the middle of the picture. This behavior is not inconsistent browser behavior - it is behavior determined by the person putting up the slide show on the blog.
To start and stop, and go forward or backward manually, move the cursor over the lower edge of the picture, and a control bar will pop up and become visible. That control bar has buttons for pause, forward and backward.
To see a larger version of the slideshow on Picasaweb, click on the center of the slide show, and you will end up on Picasaweb, where if you run the slide show, it is possible to see it in the full screen. It is also possible to change the pause between slides.
If there are any questions or comments, or something is not quite right, please add it to the comments link at the end of this message.