If the user clicks a thumbnail, the image will expand to full size.

如果用户单击一个缩略图，就会完全展开该图像。

youdao

You would have a thumbnail that you could click on to get a bigger image.

有一个缩略图，点击一下就可以看得更大的图片。

youdao

When you hover over a thumbnail, a preview of the video will begin playing.

鼠标停留在缩略图上时，会播放视频预览。

youdao

That, I think,is a very thumbnail sketch of the Judeo-Christian story.

这就是对犹太-基督教故事,主题的浓缩

耶鲁公开课 - 古希腊历史简介课程节选

His profile has a thumbnail portrait of Bagram Batman knocking out a rule-breaking trooper with a "POW!"

WSJ: A Superheroic Caped Crusade to Keep Troops Safe in Afghanistan

Remnants from the grave include bone fragments, caps of tooth enamel, and a thumbnail-sized piece of textiles.

BBC: Roman dig reveals early Christian graves

That image needs to be large so that it captures the essence of the brand, rather than a thumbnail.

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