I have a client that requires a complex HTML Image Map. I have tried to tale them out of it on the grounds of it being non-UX friendly, slow loading, and not accessible, but there adamant about it so need to find a Front end Dev that can help me out.

The main image will need to have 4 areas mapped;
Upon hover, the area covered needs to change color and also show a modal pop-up message.
Upon clicking, a hyperlink to a new page is triggered.

Must be responsive
Must be as accessible as possible - Alt Tags, Arial Labels, etc

Se an example of the image we need to use of an arch. Each of the stones will need to be hoverable & clickable.
As above, when hovered, a red color needs to be underlaid & when clicked a hyperlink is triggered.