Thumbnail
Thumbnail
A small preview image that shows at a glance what a video or webpage contains.
In Simple Terms
A thumbnail is a small preview image shown among many photos or videos so you can quickly find the one you're looking for. It's widely used on video-sharing sites' video listings and in smartphone photo apps' album screens. Instead of opening each file individually, you can instantly get a sense of its content just by glancing at it.
Behind the Name
The word "thumbnail" literally combines "thumb" and "nail" — the nail on your thumb. It conveys the idea of something as small as a thumb's nail, yet clear enough to take in the whole picture at a glance. That's exactly what a thumbnail image does: a tiny picture that lets you grasp the whole content in an instant.
Take a Closer Look!
A thumbnail is a small preview image displayed in lists and galleries to show what something contains at a glance.
On the internet and in smartphone apps, thumbnails play an important role as visual markers that help you quickly find what you're looking for among a huge amount of information.
Thumbnails generally come in two types, depending on how they're created.
The first type is automatically generated by the system, shrinking and cropping the original image or video.
For example, when you open a photo album on your smartphone, you see rows of small photos lined up.
By preparing shrunk-down versions of the original photos in advance, the app keeps data usage low and runs smoothly.
The second type is a separately designed image that the poster or creator uploads and registers for display.
This is commonly used in video sites' listings and blog article lists, where it acts like a "signboard" that sells the appeal of the content.
Rather than being an automatic shrunk-down version of the original video, this type of thumbnail is a custom-designed image with titles, text, or illustrations arranged to catch the viewer's interest, swapped in for display.
In this way, both approaches — organizing information for easy use, and conveying the appeal of the content — are widely put to use, each serving its own purpose.