change wordpress image

I have intalled a video plugin called ‘wordpress video gallery’ along with ‘addlink to facebook’. When I add a video or an article to my website, it gets posted to my website facebook page. for the article, it gets displayed correctly with the image on the article, but when i post a video, the image that gets attached to the post to facebook is the wordpress logo image. how can i change the wordpress image to an image of my choosing? i’m attaching a screenshot of the post to my facebook page with the wordpress image.

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