Copyright

When you are making a project which requires others peoples work, such as images, you need to be careful to make sure that whatever photo you use is not copyrighted.
In most places, such as google and flikr, which have photo's which you can use, if you look in 'advanced settings' you can change the settings so you are only looking up photos which you can use.  Depending on how you are going to use the photo, different photos will be at your disposal.  
Work will generally be put under these categories:

• Copyrighted - You can not use the work at all unless it is invalid because it has been over 50 years since it was made.
• Attribution - You are aloud to change, display, distribute, pretty much anything, but you must give the artist credit for their work.
• Noncommercial - This is the same as attribution, but you are not aloud to sell, or make money from it.
• No derivative works - You can use the photo for your intended purpose, but you can not change it in any way.
• Share alike - You can use their work, but it must have the same licence as they have on their work.   

So chose the category which best suits what you want to use it for.  

If you break a licence, the person who made the work will be able to sue you.