Both F5 and Ctrl-F5 clear caches.
I am using firefox 65.0.2 on windows.
On most websites, hitting F5 will not only reload the page but also download images again. Is this expected? Then what is the difference between F5 and Ctrl-F5? Is it possible to reload a page without downloading images again?
Both reload the current page. But if you use the Shift key, the cache is bypassed and the whole page is re-downloaded.