Handle unknown background formats gracefully#174

Open

argv-minus-one wants to merge 2 commits intoLinusU:masterfrom

argv-minus-one:handle-unknown-background-formats-gracefully

Commits on May 1, 2019

Skip reading background dimensions if they aren't needed.
argv-minus-one
committed
Better error message for “reading background dimensions” step.
argv-minus-one
committed