Default [Q] decompiling and compiling 4.4.2 .apk

Do you have to do some any different when decompiling and compiling android 4.4.2 apk's??? Trying to do some mod's to a Settings.apk. making the xml changes using notepad++. png changes with gimp. Added 3 lines of code to the settings_header.xml "showed no code errors" then saved. added 3 lines of code to the value.xml "showed no code errors" then saved, and add 2 48 x 48 png images to about 3 drawable folders. Now I use the same tool I decompliled with and try to recompile the Settings.apk and get all kinds of errors "I think" because i never get a compiled Settings.apk