I have multiple shapefiles, and I want to import them as image tiles.
How do I convert a shapefile into image format and then convert that single image file into an image pyramid such as that of OpenStreetMap (OSM)?
I have worked with GeoServer for backend and OpenLayers to render the map but now I am asking about converting my own custom shapefiles into OSM tile pyramid.
I guess you are mixing different things:
OSM (and different other map providers, too) deliver maps as so called 'tiles' that are delivered and organized via a so called Tile Map Service standard. You can find the specs for the URL (or folder) structures here.
You find different servers that support a TMS rendering. OSM itself uses Mapnik, that supports shapefiles, too. For example the coastlines are embedded just as shapefile.