Difference between solar dynamic wallpapers and timed dynamic wallpapers (Legacy)

A dynamic wallpaper must provide some metadata along each image that can be used later on to figure out what image(s) reflect the user's light situation the best. The provided metadata determines the type of the wallpaper. If solar metadata is provided, then it's a solar dynamic wallpaper; otherwise the wallpaper assumed to be timed. This is the primary difference between the two.

It's worth pointing out that a solar dynamic wallpaper reflects the user's light situation more accurately than a timed dynamic wallpaper. However, the solar dynamic wallpaper may not work for people living close to the North or the South geographic pole.

Rule of thumb: if you want the wallpaper to work for all people on the Earth, stick with time metadata; if you want the wallpaper to be as accurate as possible, stick with solar metadata.