How To Get Twitter to Use Your Newest YouTube Thumbnail
TLDR — Dev Card Validator or add a ? param at the end
Every share a link to your YouTube video but Twitter uses the old thumbnail in the preview?
Twitter saves, or caches images so it doesn’t have to pull fresh data every time a link is shared. This is great normally, but if the data changes, like you swapped your YouTube Thumbnail recently, Twitter can display the old image.