The following steps can performed to customise the default login page with a different image background.
1. Save a new page as Custom.HTML under [ManageEngine\ServiceDesk\Custom\Login]. This will return a totally blank login page with only the login information at the center. This proves the file works.
2. Now edit the file and add the standard HTML values such as,
<!DOCTYPE html>
<html>
<head>
<title> Page Title</title>
<style>
3. Then add the LoginFormDiv which is an important value.
4. Place the image required under [ManageEngine\ServiceDesk\Custom\CustomImages] folder. Then update the HTML file with the value parameter to add images and update it.
5. Since the login details were moved to the centre we need to align it as per our requirement, so add the Height and Width parameters for that field, so that we can move it around as how we needed.
6. Save the file, restart the application and everything works fine.
If we need to change the colour of the text, adjust the values as to where the login section has to be moved, do "Inspect element" of the customised login page and update the values and see how they work, then use the same values on the file, save it and restart for the changes to take effect.
PS: A sample file is attached.