We recently updated Smush Pro, but now the quality of ALL site images that we upload, have dropped badly. It's like we have set Photoshop to 10% quality. The original images we upload are good, but on screen they are VERY poor indeed. At this stage we may need to cancel Smush.
https://i2.wp.com/www.79design.org.uk/wp-content/uploads/2018/06/lincs-wordpress-training.jpg
This is an example. The quality is poor, but the one we uploaded was perfect.