You need to read the link I posted and install the new HTML file. As it comes, deleting files is not done from the web interface directly, you have to stick a specific URL in with the file name in, a real ball ache. If you stick the HTML on that I have linked to then you can delete files from the main GUI and you can drag and drop to upload.
The 8 Gb is not limited to 8:3 format in the file name. That limit is imposed by the file system not the size of the card. What limits it is the web interface for some reason.