Hey all, I noticed that some of my microscopy images appeared inverted after saving them with skimage.io.imsave. After some testing, here's some of the weirdness. My image is called s: ```python In [37]: np.min(s) Out[37]: 119 In [38]: np.max(s) Out[38]: 4095 In [39]: s.shape Out[39]: (1040, 1392) In [40]: s.dtype Out[40]: dtype('uint16') In [41]: io.imsave('/Users/nuneziglesiasj/Desktop/im.tif', s) In [42]: sr = io.imread('/Users/nuneziglesiasj/Desktop/im.tif') In [43]: (s == sr).all() Out[43]: Image(False, dtype=bool) In [44]: sr.min() Out[44]: Image(0, dtype=uint8) In [45]: sr.max() Out[45]: Image(255, dtype=uint8) ``` Ok, already this is not desirable... One would hope than an imsave followed by an imread would be a no-op, but whatever, let's accept for argument's sake that we want to limit ourselves to uint8. Here's the real downer: ```python In [46]: np.corrcoef(s.ravel(), sr.ravel()) Out[46]: array([[ 1. , -0.29849602], [-0.29849602, 1. ]]) ``` This is simply unacceptable. I haven't explored any more than this yet but maybe someone has an idea about what is going on here? If it helps, the problem is with imsave — opening the images in Apple Preview shows the inversion. I just wanted to know if it was some weird incompatibility between skimage and Preview, rather than skimage acting stupid. Sadly, it appears to be the latter. PS: I just tested with png and get the exact same result.