zoom: not experienced here. I just visited a page with an image that doesn't (naturally) fit; Ctrl-scroll zooms it to fit (and back)

image in same window: seems true, but i can't imagine why you'd want this

search engines: I use single letter keywords to drive this. "g foobar" searches on google for foobar. "d foobar" searches duckduckgo. "o foobar" searches on google maps. Never had any desire to "quickly change the search engine" or have custom search engine URLs given keywords.

download speed: shows in the download dialog for me