Why do some photos appear blurry and others don't on iPad?

I have read various post about blurry photos on iPad but they have not been much help. The letter i appears bottom right. I have good internet connection, I have the same issue with the same photos that use to be perfect on different devices. Click on i and it tells me poor internet connection but all is good. (see image below) I also have enough storage.

Other photos are much older, are clear and do not have i bottom right, so I’m baffled at how to get the clarity back.

Would really welcome some assistance on this please.

kind regards

Simon

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