Images: sizes, cropping and loading

Upload one image and Ghost makes several. Every image you add to a post is resized into a range of widths, and the browser is handed the whole set so it can pick the one that suits the reader's screen and connection. Someone on a phone downloads a phone-sized file; someone on a large desktop display gets the large one. You do nothing to enable this.

Two limits are worth knowing, because between them they explain nearly every "why is my site slow" question. Ghost only ever generates versions smaller than what you give it — upload a 1200-pixel image and a 2560-pixel screen gets that same 1200-pixel file, stretched. And Ghost does not compress for you: an uncompressed 8 MB photograph is resized to 8 MB-worth of pixels at every size.

There is also one kind of card that Ghost leaves out of this automation entirely, where the file you upload is the file every reader downloads at every screen size. Neutrino compensates for it in the places it matters most, but not everywhere — which is worth knowing if a page ever feels heavier than it looks.