Describe further, provide lots of details.
Can't see the images where? In Lightroom Grid in the Library Module, can't see in the Lightroom Import dialog, can't see in your operating system, can't see somewhere else?
What do you see? Tell us in detail or show us a screen capture.
Is there an error message? Please quote it exactly, word-for-word
Please state your operating system, and version of Lightroom, and camera used, and are the photos JPG or RAW, and how you are connected to the camera or camera card.
Yes, I've asked for a lot of information, please be kind enough to answer every question, not just a few of the questions.