image orientation

[somaamos]

this doesn't seem to support the image orientation (rotation?) tag in images, at least on windows

so for example, using canon camera, turning the camera to take a vertical image -- the image looks ok within windows and image apps, but when running split on it, the source image is obviously taken as landscape instead of portrait orientation and hence the resulting pieces don't match expectations

[whiplashoo]

Is that a tag in the file metadata? Is there a library we can use to detect this? I don't know if I would be able to test and add this myself, as I don't have a Canon camera, but I would gladly receive a PR implementing it.

[somaamos]

I think this is something you have to specify to Pillow -- see this method:
https://pillow.readthedocs.io/en/stable/reference/ImageOps.html#PIL.ImageOps.exif_transpose

The orientation info is stored in exif but Pillow won't adjust automatically, needs to be told to.

I think you could make test data by rotating an image using any tool which does so by writing EXIF data instead of altering image data. Most do it this way