JPEG Identify - missing Resolution

[tlichev]

Hi all,
I have an image http://s10.postimg.org/4en4ewd15/owl3.jpg

identify with ImageMagick 6.7.7-10 2014-03-06

identify -ping -verbose owl3_68243_0.jpg

Image: owl3_68243_0.jpg
Format: JPEG (Joint Photographic Experts Group JFIF format)
Class: DirectClass
Geometry: 259x194+0+0
Resolution: 72x72
Print size: 3.59722x2.69444
Units: Undefined
Type: TrueColor
Endianess: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
Red:
min: 1 (0.00392157)
max: 255 (1)
mean: 118.573 (0.464993)
standard deviation: 42.85 (0.168039)
kurtosis: 0.666621
skewness: 0.0131043
Green:
min: 0 (0)
max: 255 (1)
mean: 108.605 (0.425903)
standard deviation: 43.4648 (0.17045)
kurtosis: 0.0873388
skewness: -0.146129
Blue:
min: 0 (0)
max: 248 (0.972549)
mean: 80.3807 (0.315218)
standard deviation: 36.9113 (0.14475)
kurtosis: 1.14872
skewness: 0.428584
Image statistics:
Overall:
min: 0 (0)
max: 255 (1)
mean: 102.52 (0.402038)
standard deviation: 41.1815 (0.161496)
kurtosis: 1.23257
skewness: 0.174329
Rendering intent: Perceptual
Gamma: 0.454545
Chromaticity:
red primary: (0.64,0.33)
green primary: (0.3,0.6)
blue primary: (0.15,0.06)
white point: (0.3127,0.329)
Interlace: None
Background color: white
Border color: srgb(223,223,223)
Matte color: grey74
Transparent color: black
Compose: Over
Page geometry: 259x194+0+0
Dispose: Undefined
Iterations: 0
Compression: JPEG
Quality: 74
Orientation: Undefined
Properties:
date:create: 2016-01-25T18:35:57+02:00
date:modify: 2016-01-25T18:35:11+02:00
jpeg:colorspace: 2
jpeg:sampling-factor: 2x2,1x1,1x1
signature: bf2a343ae9dfb6d003d651420569e4c92137e71e1b09523caf7d371dfb6fd0d7
Artifacts:
filename: owl3_68243_0.jpg
verbose: true
Tainted: False
Filesize: 7.52KB
Number pixels: 50.2K
Pixels per second: 0B
User time: 0.000u
Elapsed time: 0:01.000
Version: ImageMagick 6.7.7-10 2014-03-06 Q16 http://www.imagemagick.org

there is resolution 72x72, but with ImageMagick 6.8.9-9 Q16 x86_64 2015-07-17

identify -ping -verbose owl3_68243_0.jpg

Image: owl3_68243_0.jpg
Format: JPEG (Joint Photographic Experts Group JFIF format)
Mime type: image/jpeg
Class: DirectClass
Geometry: 259x194+0+0
Units: Undefined
Type: TrueColor
Endianess: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
Pixels: 50246
Red:
min: 1 (0.00392157)
max: 255 (1)
mean: 118.573 (0.464993)
standard deviation: 42.85 (0.168039)
kurtosis: 0.666621
skewness: 0.0131043
Green:
min: 0 (0)
max: 255 (1)
mean: 108.605 (0.425903)
standard deviation: 43.4648 (0.17045)
kurtosis: 0.0873388
skewness: -0.146129
Blue:
min: 0 (0)
max: 248 (0.972549)
mean: 80.3807 (0.315218)
standard deviation: 36.9113 (0.14475)
kurtosis: 1.14872
skewness: 0.428584
Image statistics:
Overall:
min: 0 (0)
max: 255 (1)
mean: 102.52 (0.402038)
standard deviation: 41.1815 (0.161496)
kurtosis: 1.23257
skewness: 0.174329
Rendering intent: Perceptual
Gamma: 0.454545
Chromaticity:
red primary: (0.64,0.33)
green primary: (0.3,0.6)
blue primary: (0.15,0.06)
white point: (0.3127,0.329)
Background color: white
Border color: srgb(223,223,223)
Matte color: grey74
Transparent color: black
Interlace: None
Intensity: Undefined
Compose: Over
Page geometry: 259x194+0+0
Dispose: Undefined
Iterations: 0
Compression: JPEG
Quality: 74
Orientation: Undefined
Properties:
date:create: 2016-01-25T18:35:57+02:00
date:modify: 2016-01-25T18:35:11+02:00
jpeg:colorspace: 2
jpeg:sampling-factor: 2x2,1x1,1x1
signature: bf2a343ae9dfb6d003d651420569e4c92137e71e1b09523caf7d371dfb6fd0d7
Artifacts:
filename: owl3_68243_0.jpg
verbose: true
Tainted: False
Filesize: 7.52KB
Number pixels: 50.2K
Pixels per second: 5.025MB
User time: 0.000u
Elapsed time: 0:01.010
Version: ImageMagick 6.8.9-9 Q16 x86_64 2015-07-17 http://www.imagemagick.org

the resolution is missing.
Can someone explain me what is changed and why the resolution is missing? Is there any alternative to take the resolution?

[snibgo]

I suspect the file has no resolution meta-data. (You can check with exiftool.) The older version of IM used the default value of 72. The newer version doesn't use a default value.