A comparison of the image quality of the iPhone 6 versus the iPhone 7, of the same scene captured in the office. The iPhone 7 has slightly more noise, which is expected form the smaller pixel size, and appears to be less vivid than the iPhone 6. However it wins with respect to resolution quite clearly. See images below, with some analysis done in Image J.
Above zoomed image highlighting the lower noise on the left of the iPhone 6 versus the iPhone 7 on the right.
More vivid colours of the iPhone 6 on the left versus the iPhone 7, yet better definition of the plants on the right.