The Linux tool
shred can securely delete everything thats on you hard drive 1.
To use "shred" you need to boot a Linux. To do this download a Linux Mint live CD, insert it into the CD tray and power the laptop on. It will most likely directly boot into the Linux.
Part 1: Finding the files.
Linux comes with some very powerful file-finding functions, the most common one is
find. To find all the images on your hard drive you need to open a Terminal (its in your menu) and a File Browser (nautilus). Open the File Browser and navigate to the Windows Hard drives. Copy their path. Then open a terminal and type
cd followed by the path to your Windows hard drive (most likely something like
/media/mint/79054025255fb1a26e4bc422aef54eb4). Hit return.
find . -regex ".*jpg\|.*gif\|.*png" | less and hit return.
It will now search through the whole hard disk and find all images of the types JPEG, GIF and PNG - thus most likely find your photos as well. Remember the path to the photos, you will need them in the second step.
Part 2: Deleting the files
Follow the instructions to add
shred to nautilus (your file browser) here.
After that you can browse to the files you want to delete, right click them and select "shred". Then they are gone, forever.
1 Note that this assumes that you have a regular hard drive and not a SSD. If you don't know, you have a regular hard drive.
After you are done, you power down your computer and boot into windows as usual.
Alternative: Shred the harddrive and install the linux. Much easier, much saver but kills the Windows.
Boot into linux as before. Find your hard drive (its most likely
/dev/sda0). Open a terminal and issue the command
shred /dev/sda0. Then click the "Install" icon on the desktop to install the Linux Mint.