Some will use the very first image found in your page, or generate a preview that may not look good. If that doesn't bother you, then you shouldn't worry about

Some will use the very first image found in your page, or generate a preview that may not look good. If that doesn't bother you, then you shouldn't worry about it. You might be better off just having a logo for your website, or something that represents your "brand" or "identity" where it's the same for all pages, just so you avoid having a bot creating something for you in the future (which may not align with your ideas).