Raivo Laanemets. Software consultant.

ImageMagick resizes output image with bad geometry argument value

ImageMagick is a command line image manipulation library. I have used it in many projects for processing images. Recently I hit a strange bug in one of the projects where the command for adding a watermark resized the output image into the size of 10x8 pixels.

The issue occurred only in the production environment running with the ImageMagick version 6.7.7-10 but not on the development environment running with the version 6.8.6-10. The command for adding the watermark was the following:

composite -dissolve 70 -quality 100 -gravity east \
    -geometry +10 watermark.png 1.jpg 1-watermarked.jpg

Running with the -verbose argument on 6.7.7-10 shows that the output image is being resized:

watermark.png PNG 51x200 51x200+0+0 8-bit DirectClass 6.37KB 0.000u 0:00.000
1.jpg JPEG 3264x2448 3264x2448+0+0 8-bit DirectClass 2.723MB 0.210u 0:00.220
1.jpg=>1-watermarked.jpg JPEG 3264x2448=>10x8 10x8+0+0 8-bit DirectClass 0.620u 0:00.309

The reason is the (invalid) value +10 to the geometry parameter. Using +10+0 will make it work as expected. +10 however works on 6.8.6-10. The changelog does not contain any clue between 6.7.7-10 and 6.8.6-10 that the geometry parameter parsing was changed and the bug forum does not seem to contain anything about it.

Hopefully this helps to debug resize issues for someone else too.


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