Step 3: Using CMD
Open CMD by going to Start, All Programs, Accessories, Command Prompt or Start, Run, and type CMD. Type the following into the window that pops up:
Press enter. Then type:
Press enter. Now, type the following, substituting the appropriate file and/or foler names:
copy /b Picture.png + x.7z NEWPICTURE.png
This is what everything means that you have just typed:
cd\: This takes the cmd to the C Drive.
cd x: This takes the cmd to the "x" folder in the C Drive.
copy /b: This makes a binary copy of the files Picture.png and x.7z.
Where it says HIDDEN FILES.png, you should put the name of the new picture with the same extension as the other picture that was copied (my other picture was a .png, so my new one is a .png).
If you did it right, then you should have a new picture saved in the "x" folder with whatever name you gave it. You can delete the original files you wanted hidden now.