Opening or importing images saved in .asf format

I found an old SD card that contains more than six thousand photos from almost 20 years ago, when my kids were young. (these are also photos for work and of trips we took as a family, not just 6,000 baby photos.) I really want to import these photos into the Apple Photos app, or Photos library, or whatever it's called these days.

Fortunately, my 13" Macbook Pro has an SD card slot, and when I slipped the old card into the slot, it popped right up in my Finder window. All the photos are visible (that's how I know there are 6,360 of them). All their filenames look like this: "000AL0G3.ASF" (the first photo) and "00639093.ASF". I'm pretty sure the filenames are some kind of alphanumeric numbers. Not hexadecimal, as the letters go all the way up to V before they start over again. The kind of filename an old digital camera would assign to its photos internally. Glad I can at least see them in the Finder.

But Quicktime says .ASF is an unsupported file format. Photos can't "see" the files as images at all. Not even Preview can open them.

How do I save all these valuable photos from the digital dustbin of history??