In designing books, ads, websites and other graphic projects, it's common to do a left-right "flip" to make a picture or layout look better. Unfortunately, it is also common for photos to get accidentally flipped, and sometimes no one notices the flopped flip until publication -- when it's too late.
If you flip a photo, watch out for a text reversal in such things as name tags, keyboards, initial jewelry, clocks, wristwatches or signs or license plates in the background. Watch for reversed flags or logos. Make sure wedding rings are on the correct hand (usually the left in the USA).
Some products, even if made by hundreds of different manufacturers, have standard formats. Don’t reverse a telephone and end up with the handset on the right side instead of on the left, as shown above. On old televisions, knobs were almost always on the right.
Be careful if you flip a photo of a car or a truck. Remember which side the steering wheel is supposed to be on.
Sometimes a flag is supposed to be “backwards.” When the American flag is on the right ("starboard") side of an airplane (including Air Force One) or on the right sleeve of a uniform, the stars go on the right. This mimics the way the flag would fly from a mast on a moving ship or when carried into battle.