Add a way to download the original image to images admin

[rakyi]

Core problem

From Charlie:

in the new images admin, it would be helpful if there was a quick download button that 1) kept the file name and 2) was in png

very frequently I’m grabbing existing featured images or other charts, so I’d use this all the time

currently to download, it seems like the way is to expand the image, right click Save as… — but this 1) doesn’t keep the file name and 2) downloads an .avif file, which I’ve had trouble using on other platforms (e.g. Mailchimp)

Proposed solution

Add a button for each image that would let the user download the original image.