Clipboard Imager is a simple tool which will grab an image from the clipboard, optionally resize it, then save the picture as a JPEG file.
The program is compact, fast to load, and so could save you a lot of time. There's no need to copy the file to the clipboard, launch a graphics program, paste it there, resize and save, for instance: Clipboard Imager can resize and save your file in a couple of clicks.
You don't even have to enter a file name, as least not each time. If the specified file exists then Clipboard Imager will create incrementally numbered files: website1.jpg, website2.jpg, website3.jpg and so on.
The program does have a couple of notable limitations, though. There's no "custom" resize option, for example: you can choose "no resize", "320x240", "640x480", "1024x768", but if you want some other resolution then you're out of luck.
And the program will only save your files as Jpegs, not the best idea if, say, your images contain lots of text. The option to save in a lossless format, perhaps PNG, would be useful.