Simple Python

server.py

#!/usr/local/bin/python3

"""
Image capture command:
imagesnap -w 5 -t 120
fswatch -0 -d -Ee "\.jpg.+" --event Created . | xargs -0 -n 1 -I {} sips --resampleHeight 250 {} --out processed
"""

import http.server
import socketserver
import os
import json

PORT = 4040

Handler = http.server.SimpleHTTPRequestHandler

class SpyHandler(Handler):
    def do_GET(self):
        if self.path.endswith('.json'):
            self.send_response(200) 
            self.send_header('Content-type', 'application/json')
            self.end_headers()
            
            path = self.translate_path('images/processed')
            scan = os.scandir(path)  # os.scandir is new in Python 3.5 – you can use other methods (listdir) if you don't want to use Python 3.5
            files = filter(lambda x: x.name.endswith('.jpg'), scan)
            files = sorted(files, key=lambda x: x.stat().st_mtime)
            output = json.dumps([f.name for f in files[-30:]])
            self.wfile.write(bytes(output, "UTF-8"))

        else:
            super().do_GET()

httpd = socketserver.TCPServer(("", PORT), SpyHandler)
print("Spying on port {}".format(PORT))
httpd.serve_forever()