Nope image handler created the thumbnail (i.e main pic) medium pic & the large pic for you. If you read the documenattion that comes with image handler it will explain all. If you need to add a prefix or sufix - the batch export process in fireworks works really well.

One thing to check is that your product listing pic is not the same size as your product imfo pic - also make sure image handler resize is set to yes and proprtianl pics is set to 1 - all you need to do is add a product click the i icon pic up your pic and thats it 3 pics created for you no )_LRG or _MED.