花了2天时间研究iPhone中锁屏图片和墙纸到底存放在哪个文件夹，最终终于找到是这2个文件：
Library/SpringBoard/LockBackground.cpbitmap
Library/SpringBoard/HomeBackground.cpbitmap
然后需要通过http://cpbitmap.cleverbyte.com.au/这个网站转成JPG或PNG。
在此列出一些系统文件夹中的文件及用途：
Accessibility settings - Settings > General > Accessibility
Library/Preferences/com.apple.Accessibility.plist
Airplane Mode, WiFi, and Bluetooth - Also memorized WiFi networks
Library/Preferences/com.apple.preferences.network
Library/Preferences/com.apple.network.eapclient.tls.TrustExceptions.plist
SystemConfiguration/com.apple.network.identification.plist
SystemConfiguration/com.apple.wifi.plist
SystemConfiguration/preferences.plist
Calendar
Library/Calendar/* <-The asterisk (*) means all files inside that folder
Library/Preferences/com.apple.mobilecal*
Call History
Library/CallHistory/*
Clock - Includes the current timezone, and World cities, timers, alarms, stopwatches
Library/Preferences/com.apple.mobiletimer.plist
Library/Preferences.com.apple.preferences.datetime.plist
Contacts
Library/AddressBook/*
Device name
SystemConfiguration/com.apple.mobilegestalt
FaceTime
Library/Preferences/com.apple.conference*
Keyboard Shortcuts - Settings > General > Keyboard > Shortcuts
Library/Keyboard/*
Language/Keyboard languages
Library/Preferences/.GlobalPreferences.plist
Library/Preferences/com.apple.Preferences.plist
Library/Preferences/com.apple.purplebuddy.plist
Location Services - Settings > Location Services
Library/locationd/*
Library/Preferences/com.apple.locationd.plist
Maps
Library/Maps/*
Library/Preferences/com.apple.Maps.plist
Music settings
Library/Preferences/com.apple.mobileipod.plist
Notes
Library/Notes/*
Library/Preferences/com.apple.mobilenotes.plist
Notification Center/Push Notification settings - Settings > Notifications
Library/BullitenBoard/*
Library/SpringBoard/PushStore/*
Library/SpringBoard/applicationstate.plist
Library/Preferences/com.apple.springboard.plist
Camera Roll - When replacing, you should delete all files in the respected folders first
Media/DCIM/*
Media/PhotoData/*
Library/Preferences/com.apple.mobileslideshow.plist
Homescreen icon layout - Note that this will be a different file if using a tweak like InfiniFolders
Library/SpringBoard/IconState.plist
Restrictions settings - Settings > General > Restrictions. NOTE: This declares what is allowed by restrictions. If you are trying to bypass restrictions that have been set on you, just turn certain things to
Library/ConfigurationProfiles/PublicInfo/EffectiveUserSettings.plist
Library/ConfigurationProfiles/UserSettings.plist
Library/Preferences/com.apple.springboard.plist
Safari - Cookies, history, bookmarks, settings
Library/Cookies/Cookies.binarycookies
Library/Safari/*
Library/Preferences/com.apple.WebFoundation.plist
Safari homescreen bookmarks
Library/WebClips/*
Siri
Library/Preferences/com.apple.assistant*
SMS, MMS, iMessages, and iMessage/FaceTime settings
Library/Preferences/com.apple.imservice*
Library/Preferences/com.apple.madrid.plist
Library/Preferences/com.apple.MobileSMS.plist
Library/SMS/*
Sounds - Settings > Sounds
Library/Preferences/com.apple.preferences.sounds.plist
Library/Preferences/com.apple.springboard.plist
Stocks
Library/Preferences/com.apple.stocks.plist
Voice Memos
Media/Recordings/*
Voicemail
Library/Voicemail/*
Wallpaper - The HomeBackground files only exist if different from the LockBackground. CPBitmaps can be converted to PNG or JPEG with this handy website: http://cpbitmap.cleverbyte.com.au/
Library/SpringBoard/LockBackground.cpbitmap
Library/SpringBoard/LockBackgroundThumbnail.jpg
Library/SpringBoard/HomeBackground.cpbitmap
Library/SpringBoard/HomeBackgroundThumbnail.jpg
Weather - Celcius/Fahrenheit, current city
Library/Preferences/com.apple.weather.plist
Here is some slightly more detailed information on each file for those that are interested.
keychain-backup.plist - Probably a backup of data stored in keychains-2.db, which stores various passwords such as WiFi, Passcode Lock, etc. (encrypted)
Library/AddressBook/AddressBook.sqlitedb - Contacts. These are the contacts which are in the "On my i[Pad/Phone/Pod touch]" group and are synced with iCloud, and are independent from contacts synced from mail accounts
Library/AddressBook/AddressBookImages.sqlitedb - Contact images
Library/Accounts/Accounts3.sqlite - Account info for the Calendars, Contacts, App Store, and iTunes apps
Library/BullitenBoard/ClearedSections.plist - Logs the sections in Notification Center that have been recently "Clear"ed
Library/BullitenBoard/SectionInfo.plist - Notification settings for individual apps (Settings app > Notifications > [app name])
Library/BullitenBoard/SectionOrder.plist - The order of the items in Notification Center (Settings > Notifications)
Library/Caches/com.apple.WebAppCache/ApplicationCache.db - Related to data cached by websites
Library/Caches/locationd/clients.plist - Location settings for apps and System Services (Settings > Location Services)
Library/Caches/locationd/GyroCal.db - Gyroscope calibration
Library/Calendar/Calendar.sqlitedb - Calendar in its entirety
Library/Calendar/Extras.db - Extras for calendar
Library/CallHistory/call_history.db - Call history, including Phone and FaceTime
Library/ConfigurationProfiles/PublicInfo/EffectiveUserSettings.plist - Restrictions settings, such as which abilities are enabled (if restrictions are on)
Library/ConfigurationProfiles/UserSettings.plist - Appears to mirror EffectiveUserSettings.plist
Library/Cookies/com.apple.dataaccessd.[random string associated with an email account].binarycookies - Binary cookies for a specific email account
Library/Cookies/com.apple.itunesstored.2.sqlitedb - iTunes/App Store cookies
Library/Cookies/Cookies.binarycookies - Safari's binary cookies
Library/DataAccess/AccountInformation.plist - Email data sync info
Library/DataAccess/ASFolders-[random string associated with an email account] - Plist containing folder info for a specific email account
Library/DataAccess/iCloud-[iCloud email account name]/.mboxCache.plist - iCloud email info
Library/DataAccess/iCloud-[iCloud email account name]/.OfflineCache/[number] - iCloud emails cached for offline
Library/itunesstored/itunesstored2.sqlitedb - iTunes/App Store payment and download info
Library/itunesstored/itunesstored_private.sqlitedb - iTunes/App Store info
Library/Keyboard/dynamic-text.dat - Appears to be a keylog, and then an alphabetical list of full words.
Library/Keyboard/UserDictionary.sqlite - User-managed autocorrections (Settings > General > Keyboard > Shortcuts)
Library/Keyboard/UserDictionaryWordKeyPairs.plist - Mirrors UserDictionary.sqlite in a different format and as a plist
Library/Mail/AutoFetchEnabled - Plist containing one true/false value of whether Fetch is enabled for Mail
Library/Maps/Bookmarks.plist - Maps bookmarks
Library/Maps/History.plist - Maps history
Library/Notes/notes.idx - Notes
Library/Notes/notes.sqlite - Notes
Library/Preferences/.GlobalPreferences.plist - International settings
Library/Preferences/AppBackup/ - Created by AppBackup (a Cydia app for backing upp app data) if you use it, and contains app data backed up by it
Library/Preferences/com.[name of company].[name of service].plist - Settings for that service. These range from preferences in the Settings app to Cydia apps.
Library/Safari/Bookmarks.db - Safari bookmarks
Library/Safari/History.plist - Safari history
Library/Safari/SuspendState.plist - Suspended state of Safari, its multitasking is handled differently from most apps
Library/SMS/Attachments/[random string associated with an MMS]/[MMS file name].[extension] - An MMS file
Library/SMS/Attachments/[random string associated with an MMS]/[MMS file name]-preview-left.jpg - A preview/thumbnail of an MMS file
Library/SMS/sms.db - Messages, be they iMessages or texts
Library/SpringBoard/applicationstate.plist - App settings
Library/SpringBoard/DesiredIconState.plist - The current organization state of the icons on the home screen
Library/SpringBoard/IconState.plist - The last organization state of the home screen since boot, and is affected by DesiredIconState.plist and whatever is contained in /Applications and /var/mobile/Applications at boot
Library/SpringBoard/IconSupportState.plist - Acts as IconState.plist if you have IconSupport installed
Library/SpringBoard/LockBackground.cpbitmap - The lockscreen background, in the form of CPBitmap. Also used for the homescreen background if they are the same.
Library/SpringBoard/LockBackgroundThumbnail.jpg - Thumbnail of the lockscreen background, used in Settings > Wallpaper. Also used for the homescreen background thumbnail if they are the same.
Library/SpringBoard/HomeBackground.cpbitmap - The homescreen background, in the form of CPBitmap. Only exists if it is different from the lockscreen background.
Library/SpringBoard/HomeBackgroundThumbnail.jpg - Thumbnail of the homescreen background, used in Settings > Wallpaper. Only exists if HomeBackground.cpbitmap exists.
Library/SpringBoard/PushStore/com.[name of company].[name of app].pushstore - Plist containing push notification data for that app
Library/Voicemail/voicemail.db - Voicemail data
Library/WebClips/[random string associated with a homescreen bookmark].webclip/icon.png - Icon for a homescreen bookmark
Library/WebClips/[random string associated with a homescreen bookmark].webclip/Info.plist - Properties of a homescreen bookmark
Library/WebClips/[random string associated with a homescreen bookmark].webclip/startup.png - Splashscreen of a homescreen bookmark
Media/DCIM/[number1]APPLE/IMG_[number2].[extension] - Media file in the Camera Roll, be it photo, screenshot, video, or saved from elsewhere. Number1 is the number of the Camera Roll, which depends on how many Camera Rolls you've had and ranges from 100-999. Number2 is the chronological number of the file in the Camera Roll, which ranges from 0001-9999.
Media/PhotoData/Metadata/DCIM/[number >= 100]APPLE/IMG_[number of video in Camera Roll].JPG - Preview image of a video in the Camera Roll before you press the play button
Media/PhotoData/Metadata/DCIM/[number >= 100]APPLE/IMG_[number of video in Camera Roll].THM - Thumbnail of a video in the Camera Roll
Media/PhotoData/Metadata/PhotoData/Sync/[number >= 100]SYNCD/IMG_[number of video in Camera Roll].JPG - Corresponds to its parallel in Media/PhotoData/Metadata/DCIM/[number >= 100]APPLE/IMG_number of video in Camera Roll].JPG
Media/PhotoData/Metadata/PhotoData/Sync/[number >= 100]SYNCD/IMG_[number of video in Camera Roll].THM - Corresponds to its parallel in Media/PhotoData/Metadata/DCIM/[number >= 100]APPLE/IMG_number of video in Camera Roll].THM
Media/PhotoData/MISC/DCIM_APPLE.plist - States the current Camera Roll number and the number of the last media placed into the Camera Roll
Media/PhotoData/MISC/PreviewWellImage.tiff - Thumbnail of the Camera Roll when in the root of the Photos app
Media/PhotoData/Photos.sqlite - Photo data
Media/PhotoData/Photos.sqlite.aside - Appears to be some sort of backup of Photos.sqlite
Media/Recordings/[date] [time].m4a - Voice Memo, named YYYYMMDD HHMMSS.m4a
Media/Recordings/AssetManifest.plist - Manifest of Voice Memo data
Media/Recordings/Recordings.db - Voice Memo data
Media/Recprdings/SyncedAssets.plist - Sync info of Voice Memos
SystemConfiguration/com.apple.accounts.exists.plist - List of accounts that are enabled/disabled on your device
SystemConfiguration/com.apple.AutoWake.plist - List of times that the device is scheduled to automatically connect to WiFi (persistent Wifi for ya)
SystemConfiguration/com.apple.mobilegestalt - Contains the device name
SystemConfiguration/com.apple.network.identification.plist - Network info, such as memorized SSID's to automatically connect to
com.apple.radios.plist - Airplane Mode toggle
SystemConfiguration/com.apple.wifi.plist - Network info, such as memorized SSID's to automatically connect to
SystemConfiguration/preferences.plist - Network info