Here are some additional resources that dig deeper into all of these areas: Facebook help centerInstagram imagesLinkedIn image dimensionsPinterest boards about social media image sizesMedium image sizesMedium help centerTwitter sizing Want to learn even more? Once your video is uploaded, you can add or change your custom thumbnail at any time. This surprises most people, but it makes sense; while the thumbnail will be small when showing up in searches, it will be expanded to a full video’s size when it shows up as a suggestion for the next watch. Often done in groups, but can be done individuals. Usability is an assessment of how learnable a system is and how easy a user finds it to use.