I haven't got the time to check your code right now, but did you specify the wrong dimensions for each image by any chance? That's the first and most obvious cause of poor quality image display that springs to my mind.
OnePlus 5T review: Hands-on
Illustrator Andrés Lozano on his improv line work, brazen use of colours & hand sketching
iPhone X review
Comment envoyer gratuitement des gros fichiers ?