Originally, just like with the Google+ sharing feature on the google website, I could toggle between graphic previews of a shared page when using the Firefox for desktop feature (i.e. the paper airplane button), or select none at all. Recently, over the past month or so (which may correlate to a Firefox update), this feature vanished, which forces me to use whatever the first graphic preview of the website is, which for the links I'm sharing on G+, is often a third-party advertisement panel (boooo!). In the .jpg figure attached, I've circled what I call the 'graphic preview' with a red circle. (I don't know what the formal term is.) In the original behavior, arrows and an 'x' button would appear if I hovered my mouse over the preview allowing me to select to change or remove the graphic preview. Presently, nothing happens if I hover my mouse over the preview. This issue may be true of other social media, but I only use Google Plus, so I haven't tried the others. (As hard as that may be to believe.)