Simple past tense and past participle of upvote.(verb)
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Use "upvoted" in a sentence
"Also, all images can be "upvoted" which means if someone else likes your image, they can promote it with a vote."
"(reddited?) 'upvoted' that's the one .. call to stop users from submitting articles from the tabloid arguing its journalistic integrity was akin to that of Fox News."
"Things that you post on Reddit. com can be downvoted or upvoted."