Major update to the behavior of lower_quality:
- Previously, difPy would compare the file sizes to determine whether an image would be lower or higher quality.
- Starting with v.4.1.3, difPy now considers the image resolution (pixel width x pixel height) the determine image quality. This is a more accurate measure, since image file sizes could be lower for certain file types even though images would have higher resolutions (this is due to the difference in the way images are compressed with different file type algorithms).