使用Python開發檢查腳本，原理是：

1. 首先掃描所有特定后綴（ '.png', '.jpg', 'jpeg' , '.imageset'）等格式的圖片文件 或 圖片文件夾，獲取文件名，存入 allImageFiles 數組中；

2. 掃描所有代碼文件，逐行分析，若有引用 allImageFiles 內圖片文件文件名的字符串，則將該字符串對應的圖片文件列為有用圖片，存入 usedImageFiles 中；

3. 取 allImageFiles 與 usedImageFiles 的差集，即可獲得無用圖片集 unusedFiles ；

4. 輸出無用圖片集 unusedFiles 至文本內，并計算總圖片大小、無用圖片大小；

5. 可選地，可刪除所有無用圖片文件 及 圖片文件夾。

為避免誤刪，腳本執行結束后，需要對刪除的圖片文件 review。

            
              # coding=utf-8

import os, sys, codecs, re, shutil

reload(sys)
sys.setdefaultencoding('utf-8') 

allImageFiles = set()
usedImageFiles = set()

fileCount = 0

'''
upload_failed@1x.png -> upload_failed
'''
removeSuffixReg = re.compile('\d$|@\dx$|\d@\dx$')
def transferImagefileToImageName(imageFile):
    filename = os.path.basename(imageFile)
    (filenameNoExtension, _) = os.path.splitext(filename)
    imageName = removeSuffixReg.sub('', filenameNoExtension)
    return imageName;

def scanAboundentImage(paths):
    def checkImageCallback(fullPath, filename, extension):
        global allImageFiles
        allImageFiles.add(fullPath)

    # 掃描無用圖片文件 （較通用方法）
#    travel(paths, ['.png', '.jpg', 'jpeg', '.imageset'], checkImageCallback)
    # 掃描 ['.png', '.jpg', 'jpeg'] 格式的無用圖片文件，及 ['.imageset'] 格式的無用圖片文件夾 （適用于 iOS）
    travelFilesAndDirs(paths, ['.png', '.jpg', 'jpeg'], ['.imageset'], checkImageCallback)
    
    checkIfImageHasUsed(paths, allImageFiles)
    anylasisImageFilesOutput()

def anylasisImageFilesOutput():
    global allImageFiles, usedImageFiles
    unusedFiles = allImageFiles - usedImageFiles
    unusedSize = 0
    totalSize = 0
    outputFile = open(os.path.join(os.getcwd(), "uselessImage.txt"), "w")
    for aFile in allImageFiles:
        if os.path.exists(aFile):
            totalSize += countSize(aFile)

    for unusedFile in unusedFiles:
        if os.path.exists(unusedFile):
            unusedSize += countSize(unusedFile)
#            print(unusedFile)
            # 無用文件列表：輸出至 -> 腳本所在目錄下的 文本文件中
            print >> outputFile, unusedFile
            # 刪除所有無用圖片 or 目錄，默認禁用
            #removeFilesOrDirs(unusedFile)

    outputFile.close()
    print('all files count is %s \nunused files count is %s' % (len(allImageFiles), len(unusedFiles)))
    print('total size of file is %s KB \nunused file size is %s KB' % (totalSize / 1024, unusedSize / 1024))

def removeFilesOrDirs(path):
    if os.path.exists(path):
        if os.path.isfile(path):
            os.remove(path)
        elif os.path.isdir(path):
            shutil.rmtree(path)

# 遍歷文件夾，計算文件大小
def countSize(path):
    totalSize = 0
    #判斷是否為目錄
    if (os.path.isdir(path)):
        # 遍歷目錄下所有文件根，目錄下的每一個文件夾(包含它自己), 產生3-元組 (dirpath, dirnames, filenames)【文件夾路徑, 文件夾名字, 文件名稱】
        for r, ds, files in os.walk(path):
            #遍歷所有文件
            for file in files:
                totalSize += os.path.getsize(os.path.join(r, file)) #獲取文件大小
    else:
        totalSize = os.path.getsize(path)
    return totalSize

def checkIfImageHasUsed(paths, imageFiles):
    def travelCallback(fullPath, filename, extension):
        fileNameMapToCodeString = {}
        for imageFile in imageFiles:
            fileNameMapToCodeString[imageFile] = "\"%s" % transferImagefileToImageName(imageFile)

        with codecs.open(fullPath, 'r', 'utf-8') as file:
            codeLines = file.readlines()
            for line in codeLines:
                for imageFile, imageNameInCode in fileNameMapToCodeString.iteritems():
                    if imageNameInCode in line:
                        global usedImageFiles
                        usedImageFiles.add(imageFile)

    travel(paths, ['.h', '.m', '.xib', '.storyboard'], travelCallback)

# 搜索所有“文件”，篩選符合后綴規則的文件
def travel(paths, fileExtensions, callback):
    for path in paths:
        for dirpath, dirnames, filenames in os.walk(path):
            for filename in filenames:
                fullPath = os.path.join(dirpath, filename)
                (_, extension) = os.path.splitext(filename)
                if os.path.exists(fullPath) and extension in fileExtensions:
                    callback(fullPath, filename, extension)


# 搜索所有“文件 + 文件夾”，篩選符合后綴規則的文件及文件夾。文件所在的文件夾若匹配，則文件不再匹配（不匹配 imageset 內部的圖片文件）
def travelFilesAndDirs(paths, fileExtensions, dirExtensions, callback):
    for path in paths:
        for dirpath, dirnames, filenames in os.walk(path):
            for filename in filenames:
                fullPath = os.path.join(dirpath, filename)
                (_, extension) = os.path.splitext(filename)
                if os.path.exists(fullPath) and extension in fileExtensions and not isFileDirHasTargetExtensions(fullPath, dirExtensions):
                    callback(fullPath, filename, extension)

            for dirname in dirnames:
                fullPath = os.path.join(dirpath, dirname)
                (_, extension) = os.path.splitext(dirname)
                if os.path.exists(fullPath) and extension in dirExtensions:
                    callback(fullPath, dirname, extension)

def isFileDirHasTargetExtensions(path, dirExtensions):
    parentDirName = os.path.basename(os.path.dirname(path))
    (_, extension) = os.path.splitext(parentDirName)
    return extension in dirExtensions


if sys.argv[1:]:
    scanAboundentImage(sys.argv[1:])
else:
    print "Please pass the paths to check as parameters to the script"
            
          

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