web site display latest image [on hold]

Looked for a solution to have my web page displaying the latest image of a directory and update when a new image is added. Image name is unique by having date and time in it (cam-20190227-155207.jpg).

I made something using php script and

print '<meta http-equiv="refresh" content="2">';

that flashes the page every 2 seconds. However it would be good if only image is updated when new image is added in background. What is the best way to achieve this?