ESP32-cam for cheap, low power, wireless camera. Downside is hardware quality. I bought 2 and one worked. Lots of amazon reviews had similar stories.
Ardu-cam for wide variety of options. That can be plugged into a variety of MCUs.
Raspberry pi cam for easiest programming. Downside is boot time. With the usual programming it takes much longer but you can boot to webserver in a few seconds if you want to do it the hard way.