The suggested translation would actually mean "The man draws a picture with a highlighter." While that can certainly be assumed, that's not what the sentence actually says. It mentions the act of drawing, not the product/picture.
Agree. My korean friend says 그림 can be omitted
The Korean sentence must end with a verb, so it's a sentence fragment, hence the English translation is a fragment. The sentence mentions the specific man (and his action) they are talking about.
Indeed, no verb here. It's a sentence fragment.
그림을 그리는 is a modifier to the noun (남자). The man that draws...
I agree. "그림" is not in the English gloss.
It turns out 형광 actually means fluorescence and contains the character for firefly. (熒)
Technically if you put together the two characters that make up this word, it means firefly light and I just love that
the two characters are 熒 and 光 for anyone interested
螢光펜으로 그림을 그리는 남자