After uploading 189 images with no trouble I now try and it seems to upload but then the thumbnail doesn't show and it isn't a valid image. I used ftp to upload a few images to the originals folder. rescanned. found them. regenerated. then same thing. no thumbnails. small files (6kb) to 3MB all the same. regular media library upload works fine. today I added permalinks in the public option and regenerated images too. Can't think of anything else relevant that happened. It looks like some sort of error message flashes for an instant in a pink bar. No way to see what it says besides the word "enabled". Thanks for your help.