PHP 图片 保持高宽不变压缩之后imagejpeg($source,$file,100) 仍

图片品质前后对比 ： var_dump(exif_read_data($img));查看 ，严重失真压缩比为 50%。 压缩前： array (size=18) 'FileName' = string '1367000585017724053.JPG' (length=23) 'FileDateTime' = int 1367029384 'FileSize' = int 67872 'FileType' = int 2 '

图片品质前后对比 ： var_dump(exif_read_data($img));查看 ，严重失真压缩比为 50%。

压缩前：

array (size=18)
  'FileName' => string '1367000585017724053.JPG' (length=23)
  'FileDateTime' => int 1367029384
  'FileSize' => int 67872
  'FileType' => int 2
  'MimeType' => string 'image/jpeg' (length=10)
  'divsFound' => string 'ANY_TAG, IFD0, THUMBNAIL, EXIF' (length=30)
  'COMPUTED' => 
    array (size=7)
      'html' => string 'width="300" height="300"' (length=24)
      'Height' => int 300
      'Width' => int 300
      'IsColor' => int 1
      'ByteOrderMotorola' => int 1
      'Thumbnail.FileType' => int 2
      'Thumbnail.MimeType' => string 'image/jpeg' (length=10)
  'Orientation' => int 1
  'XResolution' => string '72/1' (length=4)
  'YResolution' => string '72/1' (length=4)
  'ResolutionUnit' => int 2
  'Software' => string 'Adobe Photoshop CS Windows' (length=26)
  'DateTime' => string '2013:04:26 10:56:18' (length=19)
  'Exif_IFD_Pointer' => int 164
  'THUMBNAIL' => 
    array (size=6)
      'Compression' => int 6
      'XResolution' => string '72/1' (length=4)
      'YResolution' => string '72/1' (length=4)
      'ResolutionUnit' => int 2
      'JPEGInterchangeFormat' => int 302
      'JPEGInterchangeFormatLength' => int 5519
  'ColorSpace' => int 1
  'ExifImageWidth' => int 300
  'ExifImageLength' => int 300

压缩之后：

array (size=8)
  'FileName' => string '1367000585108300044.jpg' (length=23)
  'FileDateTime' => int 1367029385
  'FileSize' => int 38802
  'FileType' => int 2
  'MimeType' => string 'image/jpeg' (length=10)
  'divsFound' => string 'COMMENT' (length=7)
  'COMPUTED' => 
    array (size=4)
      'html' => string 'width="300" height="300"' (length=24)
      'Height' => int 300
      'Width' => int 300
      'IsColor' => int 1
  'COMMENT' => 
    array (size=1)
      0 => string 'CREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 100
' (length=58)

图片只要经过那个函数的压缩，仍旧是失真的，图片文件大小压缩率为 50%。