Deleting pics leaves memory full on iPad

[Norwin]

Hi all,

I've started running out of memory on my 64gb iPad 2. I realised that I had too many photos on the iPad, as I was moving all my photos from my Eye-Fi 8gb Pro card onto my iPad. I deleted the photos via the 'Photos' app on the iPad. But there still wasn't any memory available for more photos. I checked in my Eye-Fi app, and all the photos were gone. I then went to Settings > General > Usage and under storage discovered the Eye-Fi app (Documents and Storage) was using in excess of 20gb, even though I'd deleted the photos. I deleted the app and reinstalled it, and that cleared the 20gb. I don't want to have to do this every time my iPad runs out of memory. What are the alternatives? Why do deleted photos still use the iPad memory?

Tx,
N