Trim image borders by imagemagick

When converting image format from png to jpeg, imagemagick (convert command)add margin border with bold black color automatically.

Environment

• MacOS Monterey 12.0, M1 Apple silicon
• Version: ImageMagick 7.1.0-12 Q16-HDRI arm

Problem

Getting screenshot by Command + Shift + 5 in OSX, it allows to get a screenshot for a specific window like:

Above image contains transparent background. Converting .png to .jpg by imagemagick, it generates image border in black color that I do not expect.

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convert IACDriverProperties.png -quality 95% IACDriverProperties.jpg

Solution

For removing margins, add options of -trim , -fuzz and -border to convert command

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 convert IACDriverProperties.png \
     -fuzz 30% \
     -trim \
     -border 1x1 \
     -quality 95% IACDriverProperties_trim.jpg

• -fuzz distance : colors within this distance are considered equal
• -trim : trim image edges
• -border geometry : surround image with a border of color

References

• Stackoverflow | ImageMagick - Remove black borders
• backport | ImageMagickで周囲の余白を除去する