Performance hack seen on a customer site; fix the bad LCP (due to an animation in revslider) by loading an inline (base64’ed) png image which according to FF is broken and later in the rendering process hiding & removing it.
Even though that image is not *really* used, tools such as Google Pagespeed Insights pick it up as the LCP image and the score is “in the green”.
Not sure this is really helping performance (spoiler: it’s not), but Pagespeed is happy and so is the customer. Crazy!