The Ultimate Guide to Mobile Thumbnail Dimensions for YouTube

Why Mobile Thumbnails Are Essential for YouTube Success
More than 70% of the YouTube clock time comes from mobile devices. With such a significant proportion of the audience to see the material on the small screen, the thumbnail must attract attention immediately and communicate the value in a fraction of a second.

A poorly designed thumbnail can make your video unprofessional, vague or irrelevant. On the other hand, a sharp, mobile-friendly thumbnail improves your click-wealth rate (CTR) and puts you forward in fighting for meditation.