I want to enlarge this photo to put it on the wall.
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means prolong and this verb means to prolong.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: Do you mind if I go to prolong things? The answer? "No (の), I don't mind."