to prevent raw type and unchecked warnings, suppress where needed;
mostly to reduce warnings at call sites in clients.

Release some dangling pool resources in finally blocks and reuse local variables instead of getters.

Less declared but not used exceptions.
Less tested but never thrown exceptions.

and fix the errors.

Fixes #104

Fix some comments: - typos, - documented empty blocks, - shortened some {@link}s, - converted some multi-line comments to single-line/javadocs.

Since we also try to reload the image from source,
we may end up reporting first a failure and then
a success which would leave the request in an
undefined state.

Fixes #97. 

Fixes #90

Fixes #95

Fixes #91