When can preposition 'of' be omitted?

Sentence One: The main image, which takes up the majority of the page, is of an artist's palette.

Sentence Two: These aspects are of more interest to buyers.

It seems that in sentence two, we can remove the preposition 'of' by turning interest into a gerund. These aspects are more interesting to buyers. Without the gerund, the sentence sounds awkward and is incorrect. These aspects are more interest to buyers.

In sentence one, it seems that even without the preposition 'of', and something to replace it with, the sentence seems makes sense and is not awkward. The main image, which takes takes up the majority of the page, is an artist's palette.

Why does sentence one sound fine without the preposition (is it grammatically correct?), while sentence two doesn't really work without the preposition and gerund replacement?

• They are two different uses of the word 'of'. However, I would suggest that it is better to include 'of' in the first sentence, as an image of something is not the thing itself. There's a famous painting by Magritte of a tobacco pipe with the caption (in French) 'This is not a pipe', implying 'it's a picture of one'. – Kate Bunting Oct 23 '18 at 8:21
• I find nothing wrong with using of in either sentence, and, in fact, I find they both sound better with it. Both of your why questions seem to be a matter of opinion. You've stated some things, but the rest is subjective. I can't determine an actual question that can be answered here. – Jason Bassford Oct 23 '18 at 17:25
• @JasonBassford So, These aspects are more interest to buyers. is grammatically correct? It sounds very awkward. Why does it work without of? – ShrimpCrackers Oct 23 '18 at 18:59
• No, I would not say that is correct. What I was saying is I don't see any reason to remove the prepositions in the first place. – Jason Bassford Oct 23 '18 at 19:10
• Note the the first sentence only works syntactically without the of. Semantically, it's different. (Rather than showing something that exists somewhere else, it, itself, is the thing that is used.) This, and the fact that of is used differently in the two sentences, was mentioned in the first comment here. – Jason Bassford Oct 23 '18 at 19:37