Preservation of information and computer security is broadly dependent on the secured authentication system which is underpinned by password. Text based password is a commonly used and available system for authentication. But it bears many limitations like shoulder surfing, dictionary attack, Phishing, guessing the password etc. In order to overwhelm these vulnerabilities of ancient textual password, many graphical or image based password authentication system has been introduced form last few years. But none of this graphical system is considered as enough adventurous to keep pace with these issues. Here we have proposed an image based password authentication system which is more methodical and can cope up with every vulnerability of recent password authentication system. To make our system hassle free and more reliable, we will only take username from an user for registration purpose as our system will generate a unique key number for that particular user and this key will be used as password for later login procedure. The user name and key both will be encrypted using a cryptography algorithm to prevent database hacking. There will be a randomized clickable image grid in our system. By clicking on this image grid, user will input the password key for login purpose. Here we have developed another method namely shoulder surfing resistant password. To prevent the attack of shoulder surfing, if any user wishes to change our system provided password key then he or she is allowed to do so by using this method. Besides this method allows user to change the password every single time of login. A user doesn't need to enter any textual password for authentication in our recent module and hence combination of all these features improve the security, usability and user friendliness of our system.