Good Files Rejected - Double Question Mark Icons?

[WilsonFrontier]

Recently had to re-create some galleries we had up for years without problems. Now when I try to batch add files, some of them are just not being added. The only sort of notice I get why is a double ?? icon next to the file name (see attached screen shot). The files themselves are fine. Checked them every way. Checked permissions, settings. They're identical to files that are being accepted. I can't figure out why they're not getting into the albums. I can even navigate to them manually by URL and the image shows up. Any ideas?  Thanks!

[Αndré]

Please have a look at the files names at your screenshot. After each files' extension (jpg) are additional characters. Please hover over the last columns "icons" (which aren't displayed for some reason) to get a more detailed error message.