Use Swingwork instead of blocking Swingui

Swingwork was used to download images during the recent loading of pictures, but the discovery would cause the swing UI interface to be suspended.

Looking at the information, Swingwork is designed to solve the problem of the stuck UI, normal use should be no problem, but one thing, its progress and done are placed in the EDT thread,

An excessive number of executions can result in a busy EDT thread causing the interface to die, which in turn violates the design intent.

Know the reason after the good run, directly to the Swingwork transformation into runnable on it can