Re-remove synchronized from retrieveThumbnail
Escape analysis on ThumbnailStorePrx

Track the exit of the store out of the Connector
and surround with a try/finally as much as possible.
It's a bit unclear if there is anything that can
cause the the BatchCall to not proceed until "last"
is true. If there is, that should be handled too.
Specify full number of images to load

If the full number is not specified, the state will be modified
before the loading is complete.
Sort the images before loading.
Do not display progress bar.