Catching the eye is the key to success in postcard sales. Sometimes the right image can make the difference. If you are in postcard printing and are looking for some fresh ideas for images on your cards, look into purchasing stock photography online.
Stock photography is a term for collections of photographs and other images developed by professionals. For postcard printing, stock photography can be great to provide you with many different options. Beware that your images are fairly unique. There is no sense printing postcards that others have covered already.
Unique ideas can also stem from good stock photography. If you are prone to writer's block and are in postcard printing, think about acquiring some good art to inspire you.