If every 'page' of the store takes 2-3 seconds to load all text and icons thats satisfactory. But if it takes 2-3 seconds per icon. Not so much.
It depends on how many threads are spawned to download the images (or how many async download can be made at the same time). Currently, they may seem serialized because the servers are congested. When akamaized, the client should be able to pull from a large number of hosts in parallel.