This contains cover art for "most" games. Sadly, they are very low-res, often have bad contrast/color, and are frequently ugly/wrong/non-English versions.
I'm looking for high-resolution, properly scanned/adjusted covers for classic video games, with far better QA. But it probably doesn't exist.
The one good thing I will say about "libretro-thumbnails" is that at least it uses "standardized" names, and allows me to download them all in one go for local processing, which is very important for this to be meaningful. For example:
Donkey Kong Land III (USA, Europe) (Rev 1) (SGB Enhanced).png
In my own research, I've found quite a bunch of websites which provide cover art/scans. I'm not sure if they all work independently or not, but while they usually have higher resolution images, there is no "standard path" or anything for me to fetch them one-by-one, nor any "download all data" option that I could find. As such, since this is an unthinkable task to be performed manually, I'm so far stuck with libretro-thumbnails. Sadly, it's just too bad quality, too low-res and too many errors for me to feel that it's meaningful to create a "virtual game collection" (since my physical one is sadly long gone).
As you probably understand, I want to be able to zoom in and look at the details of the covers and, of course, for them to be right ones that I remember in my visual memory and feel nostalgic attachment to. Otherwise, I might as well just have a text file with the titles of the games. Which is what I have right now.
Most likely, there is just no such thing as I'm asking for. Because it would require actual effort. And people don't put in real effort unless they get paid. So it wouldn't be free...