Locating a wallpaper that comes activated by default after ROM flashing So I have a v5.1 ROM that has this one wallpaper that automatically comes activated by default when the ROM is flashed that I wish to locate and "remove/replace" - yes I do not want to salvage the wallpaper which I am aware could be done with root and root browsing. I have unpacked the system.img and look it up in the 'media/images' directory where I have found image files on other Lollipop system.img with no success. I have also tried to bring out all JPG and PNG files that exist in all ROM folder directories and the said image file was still not amongst them. This brings me to think that it may have an extension I am not yet familiar of which one of you may be already. A pointer will be greatly appreciated.
Default wallpaper is found in /system/framework/framework-res.apk and /system/priv-app/SystemUI/SystemUI.apk. Incase of the lock screen paper

To remove it copy the .apk to sdcard and rename the apk to .zip so that it is extractable by archivers like RAR. Extract it's contents and find it at

/res/drawable-hdpi-v4 


If your phone's resolution is 480x800

/res/drawable-xhdpi-v4


If your phone's resolution is 720x1280

/res/drawable-xxhdpi-v4


If your phone's resolution is 1280x2440

They are renamed as:

default-wallpaper.png
keyguard-wallpaper.png


Their file extension can vary to jpg mostly in many devices. And as added by Andy, it can be found at  /res/drawable-nodpi resolution of device is not considered. It always persists under all resolutions

For example mine is found here
 

And it's properties are


This goes down to tv-dpi or xxxhdpi for android tv. Replace it with your favourite but ensure to keep resolution of the paper for good results, zip it again and rename it back to apk. Replace it with the system one.

Note: For framework-res.apk I recommend you to use TWRP file manager to replace it to system original apk because framework is always actively used on a boot device and will crash the system if you try to replace the apk using root on a boot device.