I digitize a map of Ponta Pora city, it's a Brazilian city, beside this I did multiple frames and export it to LeafLet where it can be accessed by a web browser.
I got the image from Google Maps.
Create a New Shape File with polygon type and right coordenation system. After this draw a geometric figure with the size of your map.
I used Georefencer option in Raster menu for opening the image on QGis.
Quick tip: If this option isn't able then it's necessary to install the plugin on Manage and Install Plugins in Plugins menu.
Add relative points.
Create a new Shapefile Layer with your new polygons areas.
Export using qgisweb to LeafLet in Web menu.
Quick tip: If this option isn't able then it's necessary to install the plugin on Manage and Install Plugins in Plugins menu.
It's necessary all layers be in the right coordenation system.
EPSG:3857