To partially answer my own question, I have found useful information about the cam webserver API here:
https://github.com/easytarget/esp32-cam-webserver/blob/master/API.md
In short, there are a few other useful endpoints, like /status and /control. In order to change resolution, the uri to access would be http://<IP-ADDRESS>/control?var=framesize&val=8
Not all the commands in the link work, unfortunately (and, quite important, the 'save_prefs' does not) but it can be used to programatically access and save frames at the specific resolution one wants, which is all I need.
It appears that the cam webserver is the standard ESP32 CameraWebServer, but I could not find an official API doc just yet. Some more info here: https://github.com/espressif/arduino-esp32/blob/master/libraries/ESP32/examples/Camera/CameraWebServer/app_httpd.cpp
I find it odd that a simple API documentation of the CameraWebServer is not offered on the product page, it would be most useful.

Hello,
I've been trying to use the CamS3 for a simple project (capture photos on demand as response to a trigger) and I have a few issues:
-when configuring the camera by connecting to it on IP 192.168.4.1, there is a "stream" button leading to address 192.168.4.1/api/v1/stream. The only issue is that stream quality is 0.3 MP. I'd like to use the full capability of 2MP. The API also supports "capture" command on address 192.168.4.1/api/v1/capture. Does anyone know how I could capture images on 2MP? Does API v1 support this? Any chance of API v1 docs to figure it out?
-if I configure the camera to save to SD card, quality is set to 640x480 = 0.3 MP. How can I change that to 2MP?
-if I configure the camera to post images to EzData, only 1 picture (the first ever) is posted, and then nothing else, no matter what I try. Has anyone had luck with that? It would be ideal for my needs (again, in full resolution)
-any plans to have other software installed? Maybe possibility to use it with UiFlow?

Thank you.

I believe the unit ToF4M is not supported by UiFlow 2.0? I can't find it listed and the ToF unit (which is probably for the '2-meter' version is not working). A recent update not 10 days ago added a bunch of units, but not this one. ToF4M is working just fine under UiFlow 1.0, but is there any way to have it work in 2.0? Maybe with an 'execute code' block? Has anyone had success?
I'd really like to use UiFlow 2 with it.