Question about image choice

Hi,
I have a problem with the images that are being shown. In 2 out of 7 cases, they are not the images from the article, and in one other case, the image does not show. Where, and in what order are the images being chosen? Here is the page where it is happening at the end of the widgets: https://www.lemondedutabac.com. Thanks for your help.

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