Hello ..
Here is an example of a flow that uses the http-request node to pull the image (data buffer) and later save it with the use of File write node.
I tried to used a Function node in between to generate a unique name for the image filename.
(it may need a little tweeking. I used the date as a filename - you may need to change that)
Example Flow:
[{"id":"92cc7228ab7e22ce","type":"inject","z":"54efb553244c241f","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":290,"y":1020,"wires":[["6fdf067fdc5f4ca6"]]},{"id":"6fdf067fdc5f4ca6","type":"http request","z":"54efb553244c241f","name":"","method":"GET","ret":"bin","paytoqs":"ignore","url":"https://regiowebcam.de/fileadmin/user_upload/01_storch_kirchzarten2021.jpg?ver=1639302266349","tls":"","persist":false,"proxy":"","authType":"","senderr":false,"credentials":{},"x":480,"y":1020,"wires":[["337ff149a1b382ad"]]},{"id":"3174f03bedd6f49b","type":"file","z":"54efb553244c241f","name":"","filename":"","appendNewline":false,"createDir":false,"overwriteFile":"true","encoding":"none","x":880,"y":1020,"wires":[[]]},{"id":"91a3b46f1bebdf71","type":"debug","z":"54efb553244c241f","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":830,"y":920,"wires":[]},{"id":"337ff149a1b382ad","type":"function","z":"54efb553244c241f","name":"","func":"let now = new Date().toISOString().replace(/:/g, \"-\")\n//node.warn(now);\n\nmsg.filename = `c:\\\\users\\\\user\\\\desktop\\\\${now}.jpg`\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":680,"y":1020,"wires":[["3174f03bedd6f49b","91a3b46f1bebdf71"]]}]