comment on

Handwavy outline.

Use Imager to load the image
Start at the top row. Assume the width of the transparent extent for both left and right is the width of the image; similarly the top and bottom is the height.
Walk each row and find the length of the transparent extent to the left and right
If that length is less than the current maximum, remember it as the new current maximum
At the same time you're going to want to look and make a similar determination for the extent in each column
After you've walked down each row you know the width of the left most and right most transparent chunks; so crop horizontally from there over. And you should also have the vertical extents as well.

The cake is a lie.
The cake is a lie.
The cake is a lie.

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