A question about mobile RAM usage and images displayed in browser

This is sort of a general question but it's more relevant/significantly affects mobile devices I think more than a desktop computer.

I built this cloud-based web-application that loads A LOT of images, I'm talking 300+ images which used almost 60MB. That doesn't like much. I do preload the images and don't show them/add them to the page until they're completely downloaded. In general each image is less than 200KB in size and takes less than 100ms to load (some 20ms some over 200ms).

I'm just wondering when a browser loads an image, once it's on your end, when the browser is displaying it, does the browser need to take up as much RAM to display that image as big as the file size is?

I'm sort of confused.

I realize too that 60MB compared to 1GB of RAM, you know... what is that?

But I don't know why I'm not understanding the relationship between an image displayed be it on a browser or a local image viewing program and the image's file size regarding RAM usage.

I'd appreciate any light on the subject.
 
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