Problem solved! Bennor, thank you so much for your advice. You pointed to the exact place of problem. In case any one has the similar problem, here is how to solve:
step 1: open a browser such as Chrome and go to port 9000 of MyCloud, i.e.,
http://“my cloud server ip#”:9000
step 2: click “Sharing” in the left column (the third item under SETTING);
step 3: scroll down the page and find “[TV] Samsung xxxx” (some info about the TV) in the second list, “Media Receivers”. In my case, the Media Receiver Type was “-/-” which was the problem. Click on it, then a long drop-down list enumerates hundreds of device types. I chose “Samsung Smart TV”.
step 4: Click the “Save Changes” button at the bottom of the page.
Large JPEG pictures (as big as 15 MB) are displayed properly by the smart TV. I love WD MyCloud again.
