I read your post on black thumbnails. I went to the media manager and uploaded diectly a .jpg and I still have a black thumbnails. Please advise, thanks.

PS I have looked at al forum posts on this topic. I have checked permissions, I have ensured no spaces, and I have ensured that all files were .jpg .

I have the same issue. All thumbnails are black. Inspection shows they give a 404 on the cached images, but on the server folder and images are there right where they should be.
It happens with Simple Image Gallery and Simple Image Gallery Pro.
On the site caching is disabled.