This tool can be used to embed slide shows or videosequences into a scene. It creates a rectangle on which the images are displayed. The rectangle is always directed to the camera position. Its position in space can be changed by hand.
The property pictures is a path pattern to the image files. You can use a path with a placeholder for the frame number according to the python format syntax.
points for frame 567 to
An image is shown until the next file with a suitable filename ist available. Then it's replaced by that one.
So you can hold images for a longer time on screen to get the behavior of a slide show.
If you have
/home/freek/pics/my_picture_0567.png and next
/home/freek/pics/my_picture_0617.png then the first picture will rest for (617 -567) = 50 frames, this is normally 2 seconds.
The dimension fo the rectangle is by default 64 x 48. You can change it in the rectangle objects property tab. The length hight ratio should fit the ratio of your images to avoid distortion effects.