[PeterisP]

That's the point, they do not have plenty of contrast. In the very first "good example", the phrase "Explore popular tourist destinations..." is needlessly difficult to read for me, and "28 reviews" might as well not be there; it's difficult to notice and I need to strain my eyes to read something with that low contrast. That picture is a clear example of something that's hard to use for many people, doesn't satisfy official accessibility standards, and should not be recommended.

Maybe you're younger or have better vision or a significantly different screen than I do, but then let that be a warning that either you need do usability testing on some settings where that particular picture looks not sufficiently 'contrasty' to you as well, or you need to write down the RGB values that this image has with a note "that's not enough contrast for general usage even if it looks ok to my eye".