Maybe it’s something in UI, but many times I watch pictures (not even videos, they are their own can of worms), and want to save them, it shows me that I’m downloading them again although they are cached in whatever app I see them from.
Like this link with a happy dog: https://i.pinimg.com/736x/71/1e/52/711e52f1d6c7ead78f4380214f68c259.jpg
I see it in high rez in my browser, I can zoom in, and I can’t tell any difference from a copy that I can download, but it’s still, well, another download if I want to save it, and not a move from cache to my download folder, another request to the server, another waste of traffic.
Is there some rule of sandboxing for everything you load that I don’t know about? In cases like our fediverse, I wouldn’t like to cause double load when I already have the picture I want. Can I cut it down with some plugin in mobile Firefox?
I feel like I’m missing something big time.
It’s simpler code to re-download the file than retrieve what cached version may or may not exist in memory or on disk. Developers often like to keep code simple at the expense of some kinds of efficiency, like this.
An image is usually small enough to be downloaded in no time on a fast connection, which is what developers usually have and don’t stop to think that others might not have.
A video is probably being streamed so earlier segments may no longer be present locally.
It’s simpler code to re-download the file than retrieve what cached version may or may not exist in memory
This seems incredible
There would already have to be a data layer that serves the main web page renderer. That layer would already have to handle looking in the cache or making an http request in event of a cache miss. It would seem almost trivial for a UI operation like ‘save to disk’ to simply call that layer in the same way
For a few hundred K image file I can understand why some might not bother, but I’ve seen this behaviour where a browser already has an MP4 cached (such that it can replay any part of it without subsequent http traffic) and yet it still makes a new request when saving. It’s weird to be honest…
Have often wondered this myself, would love to know the answer
Yeah, sometimes I even then can’t download the picture, even though I was looking at it just then, because the server can apparently tell the difference and returns an error code instead.
I notice this with pdfs. I view a pdf in browser and then when I want to download it the damn thing has to come down again.
For what it’s worth, I recently swapped to Linux and discovered this doesn’t seem to happen there.
