Using an image of height:0 width:0 for SEO

I still have some unfamiliarity with SEO. Here is what I think I know:

Using an image of height:0 width:0 for SEO

I still have some unfamiliarity with SEO. Here is what I think I know:

Can I Replace H1 text with a logo image?

Doesn’t use an h1 tag. Not as good for SEO, right?