Thumbs up and down images, and their different meanings.
Ancient references to the thumbs up or down in the Colosseum, and what is
encountered on the Internet, have different meanings.
In Internet thumbs up - acceptance, approval, satisfaction, or encouragement,
"Okay"/ "All is well" , and thumbs down - the opposite.
When using these types of images in context - remember about other meanings
for this gesture.
Hitchhike - in some countries, most of the drivers probably had no clue why
that American-looking traveler was sitting on his backpack with his thumb
extended. For example, in Russia, we will stay close to the rode with an
extended right palm. But, in any case - consider it!
In some places it can means "One" or "You are only one".
In some place it can mean "sexual insult".
Check this out: "Iraqis are giving passing Americans the "thumbs up" sign, which
the troops interpret as a symbol of support. But many veteran travelers insist
that the gesture is a crass Middle Eastern insult.."
http://www.slate.com
"In the United States and most of Europe, it means "OK" and is inoffensive. The
OK sign is used extensively in scuba diving. It can also mean "0," or "money,"
in Japan. However, in Germany, it is often seen on the Autobahn, as a silent
way of calling someone an "Asshole" (with the fingers extended horizontally).
Similar vulgar meanings are found in other countries, but usually you have to
turn the 'Ring' upside down (supinated to show the ring in front) like this
example from Brazil."
http://en.wikipedia.org