Ah, I misunderstood.
Drag and drop works for images outside the vault.
When the image is in the vault, it needs to be selected (since it is already present, there is no sense in it being added again), so that’s just a ![[ and selecting from the list which will appear. Won’t need to be typed - though a few letters will speed filtering.
If you are already writing, that’s actually likely to be faster than any drag and drop since there’s no need to use the mouse and no need to find the file.