"App Protector" might work for you. You can add any apps you want to be password protected. I especially like that it can use an unlock code too. Of course you would have to lock the camera apps completely to go this route.
If it's only a few pics you want to hide try moving them to a new folder with a ".nomedia" file in it. Doing this will hide the images from your gallery. You can then access the images in a file manager like astro or something. If you're paranoid you can then use app protector for astro and all the possible work arounds (market, any task killers, etc.).
I'm sure these aren't the only solutions but hopefully these are decent options for you.