Cache uploaded (init, controlnet, ...) images if unchanged

[SharkWipf]

Feature Idea

Currently, it seems like init images (and presumably controlnet images etc too) are re-uploaded every new run.
On my 3090, tunneling over SSH via WAN from a slower network, this can easily be the slowest part of the process on bigger input images (i.e. cycling upscaled output back as input), even when batch-generating 4 images at once.
In fact, I had to throttle my connection because my brother kept complaining about the internet going down for 8 seconds every time I hit the generate button.

Ideally, if unchanged, the image would be cached server-side and not need to be re-uploaded every time.

Other

No response