I'm very new to Pi... but old to computers.
Once you have things set up right... I can do this bit!... an IpCam can serve an IMAGE to a web browser in response to a command. I use this across my lan to look at what different cameras are seeing at the moment.
When you fetch a page this way, you don't get a page of html with an img tag leading to an image on the screen, but the image itself (which also appears in the browser, looking much like the result of the html- with- img. But for my wants (read on) the difference matters.
Something like the following is all that it takes.
I managed to write a Windows program to fetch an image from such a source, and save it to my hard disk. It can be done! (I don't want to go the "camera sends image by FTP" route... because I want to use the Pi to control when images are fetched.)
Now I'm hoping to do the same with a Pi, with the Python normally "attached" to Thonny. Using Thonny for the development work.
And have that happen when a simple push button connected to the Pi is pushed.
For the moment, it will be enough to store the image somewhere on the SD card, using the same name over and over again, overwriting whatever was in that file previously each time. (I'm assuming that sending the data to a different storage device, say a usb hard drive, would be a trivial tweak, once the rest of this is in place.
Not a small ask, but... I'm hoping that some kind person will write the code for that, post it here for us all. Not JUST out of the kindness of their heart, but because the challenge amuses them?
I'm hoping the program will be well structured, to make re-using the various parts easy.
In related news: If anyone could post a URL for a site that will serve up small .jpgs to "the public", to simulate the image-from-IpCam, that alone would be a help, in that it would be helpful to people trying to help me in this quest.