Does it matter what size memory storage your camera uses? As far as the camera is concerned, no. However, it could mean the difference between getting the picture you want or running out of space on your memory card.
When choosing the most suitable size, consider how many pictures you usually take each time. If you travel the world, then your needs will be different from a person who just uses a camera during a family gathering. You also need to decide on the quality of the pictures you take. Lower quality pictures for the internet takes up less space and enable you to fit more on a card. Larger files for printing will require more space.
If you have a 2 mega-pixel digital camera, 128MB is usually enough. For a 3 or 4-megapixel camera, a 128MB or 256MB memory card is adequate. For a 5-megapixel camera, you should get a memory card with more than 256MB.
Here's a rough guideline of how many pictures a flash memory card can store:
Whatever your decision, remember you can always use several smaller cards and just switch them when they are full. It only takes a few seconds to change memory cards, so don't worry if you don't have a large capacity memory card.