The name might not give you the right direction for a visual impression. Since most plastic particles are very small and most of the garbage floats two feet below the ocean surface, do not expect to find islands of garbage or anything like a large object nor landfill. All kind of plastic items of all kind of sizes float to the middle of a gyre and then stay there. During this journey and over time the plastic breaks into smaller pieces. These pieces are what is often referred to; the Great Pacific Garbage Patch. The shocking part is the high concentration of six times the concentration of plankton, which is the most common food for sea live. A large soup of plastic would be the best way to visualize the Great Pacific Garbage Patch and many garbage patches.Please see the visuals at this page about the Great Pacific garbage patch.
1. This page contains frequently used garbage patch pictures: http://www.algalita.org/gallery/expedition/
2. Frequently used and very good quality pictures about the subject of garbage patch pictures are photos of dead birds. Chris Jordan put a collection of pictures together about dead birds and their stomach content. These pictures can be shocking.
3. Garbage Patch Pictures of field research at the ocean: http://www.nbcbayarea.com/enjoy-this/Images-from-the-Great-Pacific-Garbage-Patch-52981802.html
4. Interesting news article with nice hand drawing of a garbage patch http://i.imgur.com/E6bxr.jpg