I have just uploaded several jpegs via ftp into the folder I created. I go to batch upload, choose that folder- I can see the pics listed but there is no checkboxes beside them. If I click OK- it says that files must have proper extensions (jpegs, etc).
I'm not sure what changed because yesterday I was able to upload and add 2 pics to my album doing this the same way!
Read up the upload troubleshooting section of the docs and do exactly as suggested there.