There is a caption under the picture.

图片下边附有说明。

《新英汉大辞典》

“The external antenna on iPhone 4 is located in the stainless steel band,” reads the caption under a photo indicating where the problem exists on Apple’s page (image to the right).

“iPhone 4的外置天线设计在外壳的不锈钢圈上，”一张出现在苹果主页上显示这个问题的图片（右图）下方的说明文字。

youdao

Caption: Fisherman in the shallow waters of the Euphrates under the Hindiyah Bridge.

描述：欣迪耶大桥下，渔民在变浅的幼发拉底河上。

youdao

Under the photos, the paper ran the caption "the prison guards have arrived".

BBC: Greece referendum: Democracy versus the eurozone

With hundreds of new pictures added to the more popular newsgroups daily, each taking as much as a minute to download, the need for one-line image descriptions puts even the most inventive caption-writers under strain.

ECONOMIST: Hard sell