Did you delete the pictures while you had the SD card in your computer? What happens for me is that when doing this, the pictures are actually moved to a hidden "Trash" file which is located on the SD card and not permanently deleted until you empty it (similar to what happens with normal files on your computer).
When you remove the card do you right click the icon on your computer and select "safely remove object" or do you just pop it out? On my computer, when I go to safely remove the card (and I've deleted some files), a dialog will pop up asking me whether or not I want to empty the trash, to which I reply yes. The computer then "works" for a few seconds deleting the files and then the icon disappears, and I remove the card.
It's always a good idea to "safely remove" items like SD cards, Flash Drives, External Hard Drives, and other separate physical devices before actually physically disconnecting/removing them. It only takes an extra second or two of your time and is a good way to prevent loss of data/other types of confusion.
The beauty of a LEGO MOC is not the elements that go into it, but the way those elements are put together.