This is the 1474th most frequent Korean word.
트위터에
"On Twitter."
In this sentence, '트위터에' uses the location marker '-에' to denote Twitter as the location where the action (posting) takes place.
나는 매일 아침 트위터에 글을 올린다.
I post on Twitter every morning.
Here, '트위터에서' uses the location marker '-에서' to indicate the setting where the discovery of the picture happened.
친구는 트위터에서 재미있는 사진을 발견했다.
My friend found an interesting picture on Twitter.
In this example, '트위터에' is used with the verb '전달하다' to indicate the platform used for delivering the message.