Should be as follows:
cp -r !(Default.png) /dest
If copying to a folder nested in the current folder (called example in the case below) you need to omit that directory also:
cp -r !(Default.png|example) /example
Should be as follows:
cp -r !(Default.png) /dest
If copying to a folder nested in the current folder (called example in the case below) you need to omit that directory also:
cp -r !(Default.png|example) /example