Here's the full story on what happens when you delete photos and how they can be recovered most successfully...
You can often recover deleted pictures from a camera memory card or USB Memory stick. However, to increase the chances of being able to recover pictures after they have been deleted you must not save any new photos, files or data to it.
When you delete pictures (or any files) from a memory card or USB memory device the data itself isn’t deleted, just the file system pointers that says where the data for those files is located. The area where the deleted picture data was stored is also now marked as free space so it is available to the system for any new files to be written there instead.
If and when that happens, then it is too late to recover your deleted pictures so it is very, very important that new pictures or files aren’t saved to the memory card in the meantime.
One of the easiest ways to see if your deleted pictures can be recovered is to try some photo recovery software.
One tip is to try a demo version of a commercial product that will scan the memory card for deleted pictures and show you exactly what pictures can be recovered. At least that will show you if you can recover the deleted pictures or if it’s too late already.
You can find more useful information on how to recover deleted pictures from a USB memory stick or camera card at