Don't use a single sprite! For what you want to do a tilemap is the way to go. Because a tilemap re-uses identical tiles, it saves you a lot of memory and is also more efficient to draw on screen.
Use this tool to extract the tiles from your map image: http://renderhjs.net/shoebox/
delete all doubles and create a tileset.
Then use this tool to create your map with the tileset you made before:http://www.mapeditor.org/
The maps you create with this tool can be loaded directly into Construct 2 (read the manual
on how to do)I advice you to search the internet on general information about tilemaps in video game design
for you get an idea of how it works.