Here's a picture of icebergs, bergy bits, growlers and even smaller bits of ice. There are standard definitions for how large ice has to be to be called an iceberg, and also for what smaller bergs are called. Basically, an iceberg has to be more than 5m above sea level, a bergy bit is about 1-5m above sea level and growlers are smaller bits of ice. They all have to orginate from glaciers or an ice shelf (taken from the National Ice Center FAQ). At Rothera Research Station ice does break off glaciers and depending on the wind direction ice can fill up the surrounding bays, like in the photo below.

The reason why parts of the icebergs are blue is to do with air being trapped inside the iceberg and the way light is absorbed and scattered by/through an iceberg - what happens is light enters an iceberg, and some colours are 'removed' by the iceberg leaving a blue colour for the human eye to see. The top of an iceberg will tend to appear white because this absorption/scattering process doesn't kick in until light penetrates deeper within the iceberg. For more iceberg info try this iceberg FAQ, this iceberg web page, Gander Academy iceberg page, the American Antarctic Program's iceberg FAQ, this website about colour and this site about icebergs.