The text is saved forever. The image can be taken down from the hosting website and made inaccessible to those viewing the blockchain.
Right now our best bet is to use https://ipfs.io. I'm surprised that IPFS isn't getting too much love here. Bitcoinfiles can only go to 5kb and today I see their SSL cert is broken.
Need your help on this one guys, can someone respected member of the community download the memo-master.zip archive on github and post the SHA hash to independently verify the file?