SUMIT TRIPATHI For very first starters you could at least mention what banking app this is. There are hundreds, if not thousands of banks worldwide with many of them have their own apps. Here in Germany alone we have dozens of banking apps. By telling us what app you are using, other people could possibly chime in if they have similar issues.
The poor rendering of the background image could very well be related to the app itself, what makes you think this is caused by your phone? Do you have another phone running the same Android version which renders the image as it should? Have you already contacted the bank about this issue?
