How to remove an image saved as wallpaper from lock screen android 4.4.2 Micromax Canvas 2 colors with android 4.4.2 is my first smart phone and im finding my way around slowly. Please can someone urgently help with my issue below?

Recently i saw an image on a website of google chrome and i clicked on the image and pressed save image. I got a message saying image downloading. later i opened the image from gallary did some size changes as it requested then made it my wallpaper for lock screen. 

However I am unable to remove the image now from the lock screen and go back to default image. Please can you help me understand where is the image stored for me to go ahead and delete this image so that it goes back to the default option of the phone, when it allowed the default wallpaper in the screen and if i played an App called Saavan it would put that albums image as the lockscreen image automatically.

Kindly advice.

Regards.
Images Downloaded from chrome are stored in ‘sdcard‘-‘download‘ if you dont have sdcard check in Internal memory's ‘download‘ directory.
After finding Image Delete it and change your wallpaper either from settings->display->wallpaper or by pressing and holding on empty space on homescreen and than selecting wallpaper.