More screenshots

[Malvoz]

Static maps, poly features, and HTML annotations example pages have been completed since last time screenshots were added, so adding the corresponding screenshots for the implementations.

Also updating the current screenshot of "Display a map centered on a point location" to an image with an actual marker to better match the description of the use case: "Usually, the map layer is at a zoom level that shows streets and points of interest, with a pinpoint marker showing the specific location."

I also made sure all files are appropriately compressed, including existing ones.

[AmeliaBR]

Another great addition, thank you.