AutoScreenCap is a lightweight Open Source screen capture tool. It is a small software does like what its name describes: auto screen capture. It allows you to make screen shots periodically and automatically save to the folder in JPG format. It is fully customizable, the capture interval can be set from 1 second to 99999 and the JPG quality also adjustable. It can be set to auto hide the main windows and auto start screenshot capture for special purposes.
Although the last update of this tool is back in 2012, this software still work fine in the latest Windows 8.1 64 bit.
It does not require installation. So basically extract the zip file to a folder and run AutoScreenCap.exe