bulk cropping PNG images which were previously rotated with Imagemagick using
convert thistle-7gn.png -rotate 75 thistle-7gn-75.png
this command
magick thistle-7gn-75.png -gravity center -crop 1600x1600+0+0 +repage thistle-7gn-75-cropped.png;
[EDIT: images appear to be converted from PNG to JPG when I upload]
[EDIT 2: Imgur converts large PNG to JPG intentionally—links to original PNG]
https://spinhead.com/thistle-7gn-75.png
https://spinhead.com/thistle-7gn-75-cropped.png
with the attached image results in the off-center crop, also attached.
my understanding of the command is to use 'magick' rather than 'convert', then filename, set the origin to center rather than top left using '-gravity center', crop to size X by Y plus offset of X-direction Y-direction FROM THE CENTER OF THE ORIGINAL IMAGE, output new filename
I have successfully done exactly this process multiple times in the past months and thought I had crop with gravity sussed, but despite using what appears to be the same syntax with different images, it's not behaving as I expect.
Mac Mini Monterey, ImageMagick 7.1.1-15 Q16-HDRI x86_64 21298
Your input PNG, which I was able to download from thistle-7gn-75.png has a virtual canvas offset, which I can see from identify -verbose thistle-7gn-75.png
as Page geometry: 4374x4374-587-587.
That means you need to remove the virtual canvas offset using +repage right after reading the input PNG.
So the following now works fine in Imagemagick for me.
Input:
magick thistle-7gn-75.png +repage -gravity center -crop 1600x1600+0+0 +repage thistle-7gn-75-cropped.png
Result: