White and grey grids in GrayscaleAlpha Type Images are converted to Black after processing in ImageMagick

[Susee]

Hi Team,

While processing the image having alternate white and grey grids around the image in the background, the image background is converted into the black color.

Is this is the actual system behavior or a bug?

Version: ImageMagick 7.0.8

Please find the image properties below:

Code: Select all

Format: PNG (Portable Network Graphics)
  Mime type: image/png
  Class: DirectClass
  Geometry: 1348x2000+0+0
  Resolution: 37.8x37.8
  Print size: 35.6614x52.9101
  Units: PixelsPerCentimeter
  Colorspace: sRGB
  Type: GrayscaleAlpha
  Base type: Undefined
  Endianess: Undefined
  Depth: 8-bit
  Channel depth:
    Red: 8-bit
    Green: 8-bit
    Blue: 8-bit
    Alpha: 8-bit
  Channel statistics:
    Pixels: 2696000
    Red:
      min: 0  (0)
      max: 255 (1)
      mean: 227.66 (0.892785)
      standard deviation: 48.6503 (0.190785)
      kurtosis: 7.54364
      skewness: -2.5977
      entropy: 0.444528
    Green:
      min: 0  (0)
      max: 255 (1)
      mean: 227.66 (0.892785)
      standard deviation: 48.6503 (0.190785)
      kurtosis: 7.54364
      skewness: -2.5977
      entropy: 0.444528
    Blue:
      min: 0  (0)
      max: 255 (1)
      mean: 227.66 (0.892785)
      standard deviation: 48.6503 (0.190785)
      kurtosis: 7.54364
      skewness: -2.5977
      entropy: 0.444528
    Alpha:
      min: 0  (0)
      max: 255 (1)
      mean: 84.7068 (0.332183)
      standard deviation: 119.911 (0.470239)
      kurtosis: -1.4896
      skewness: 0.712598
      entropy: 0.127122

[fmw42]

What was your exact command line? Can you provide our image?

[snibgo]

@Susee: for a sensible answer, you must show your input image and the command you used. Otherwise we can only guess.

For example, your input has transparency. JPEG can't record transparency, and perhaps you save the output as JPEG.