On a small size, they look fine. But when you zoom in a little, you see the lack of details, the blotchy post processing, and the graininess of the image. Daylight shots are not too bad other than colour reproduction being a little poorer than the S6. But lowlight shots are pretty bad compared with the S6, and the lack of OIS certainly did not help at all.
Just look at the image at 50% crop. (no point going 100% since no one actually zooms in that much) when viewing normally.
M9:
View attachment 175232
S6:
View attachment 175233
But in the end everyone has different needs and preferences from a phone. For social media and viewing on phones, the images looks okay to me too.
The sky did actually look like that. It was very early in the morning and the sun was just starting to rise.