Location of stock wallpaper and external battery recommendations?

[Son Nguyen]

I've been looking through the files and can't find where the stock wallpaper is. Anybody know? Also, does anyone have a recommendation on external batteries for the One? One more thing, what is the easiest way to back up the One? I know I can easily transfer photos and videos off of it but I was thinking more of a one touch/button solution? Maybe HTC Transfer can do that but I had to uninstall it because it keeps restarting itself making it unusable. Thanks.

P.S. I as able to finally get some camera usage last night, indoors low light and was amazed at the difference in pics compared to my wife's iPhone 5.