Adding icon@2x.png into SVN under OS X

If you develop iOS based apps you will come to this issue sooner or later.

shell> svn add Default\@2x.png 
svn: warning: 'Default' not found

In order to avoid this issue simply add empty revision version followed just after additional “@”.

shell> svn add Default\@2x.png@

This is not clearly stated in manual, but you can pass revision version to add as well.