pictures tips.
you can use a program called Axcrypt to encrypt your images. it's also possible encrypt them all in one go in a folder. once Axcrpt is installed, you right-click the picture/folder and select encrypt, you fill in a password, then it will start encrypting. it's a proven top program and free. to decrypt, right-click select decrpyt, fill in the password you used and that's it
http://axcrypt.sourceforge.net/
your Hard Drive makes a note of where everything is stored. so when you delete something from your HD it's still there, it's just your computer won't have a record where it is any more. there's software - freeware and payware, that can retrieve it for you.
one very good way to make it almost impossible to get the picture back is to the freeware program Eraser. what Eraser does is over-write the file lots of times, i think the default is 35 times. it's just like Axcrypt, right-click then select erase.
http://www.heidi.ie/eraser/
there are other programs too which can hide folders within pictures. i've never used them though.