[Tuna-Fish]

Oh no, it's still downloading the one it's displaying on screen. You can even see a spinny thing as the icon of the tab on Chrome.

The format allows for showing images when they are partially downloaded, and also allows pushing data that doesn't actually change the image.

[netizen-936824]

Okay? So we still seem to have an accurate representation of the image we want. Why can't I just download that and what's the point of the rest of the data. If we already are seeing the image, the rest of the data is pointless no?

[gipp]

Certainly so, yes. But your browser doesn't know that.

[chii]

but the browser doesn't know that the image is already done, and since there's still data coming in, the browser is obliged to continue downloading.

you could right click, and copy image, rather than save as. It achieves what you wanted - save a copy of the image.