Conveniently, some of the photo has been cut out, to show fewer people in the audience.
The photo has been conveniently edited to show fewer people in the audience.
省略で嘘をつくということですか?
その場合は「Conveniently, some of the photo has been cut out, to show fewer people in the audience.」を使用します。
写真や記事なら「cut」や「edit」と言います。
「Conveniently」は、文の先頭または関連動詞の前に使用できます。