Just an added thought....................Preparation is very,very important when doing this technical job of hanging pictures on cement walls.
Before you do anything involving electrical tools, make sure that you have put at least 3 and preferably 4 beers in the frig, prior to starting any job like this. The number of beers should be a ratio of 1 beer for every 4 pictures you want to hang. Next, plan the job for a time when your wife or girlfriend will be gone, otherwise you should plan on twice the amount of time it would normally take to do this technical work!
If you hang more than 12 pictures in one day, do not be surprised if some of them look as if the foundation on your home has settled 5 or 6 inches, causing the pictures to hang at a slight angle. Sometimes jobs like require a friend to help hold the screws or inserting the plastic plug. If you decide to have a friend help, make sure that she is tall enough to hold the ladder and not a close friend your wife. (She will brag about the help she gave you hanging the pictures)
Lastly, if you run into any problems of any kind, there is a great website,
B&Q Online: From Kitchens & Bathrooms to Sheds & Paving; plus planning tools. Good luck and keep the drill away from your wife.