A filename extension is very important in the Windows operating system and it appears at the end of the file name.
Not only can you instantly tell what type of file format, whether it is an image or an executable application, Windows can also decide what program to launch it with based on what is registered in the default programs list.
Generally you should pay more attention to the executable file format such as .EXE .COM .SCR .BAT .VBS .PIF and .CMD because it can be malware instead of a legitimate program. For example, an ebook that should be in a PDF or EPUB extension shouldn’t be .EXE although it is still possible if it is wrapped with a third party ebook compiler to protect against illegal distribution.
Since Windows users are more careful with executable extension and pay less attention to safer extensions such as image formats, there are a couple of ways to trick the careless user into thinking that an EXE file is a JPG image file instead.
By using this simple java cross platform spoofer you can simply trick many users in clicking your designated file.