Should be bts-background.jpg I assume:
make[3]: *** No rule to make target 'programs/qt_wallet/htdocs/img/btsx-background.jpg', needed by 'programs/qt_wallet/qrc_htdocs.cpp'. Stop.
CMakeFiles/Makefile2:2057: recipe for target 'programs/qt_wallet/CMakeFiles/BitShares.dir/all' failed
make[2]: *** [programs/qt_wallet/CMakeFiles/BitShares.dir/all] Error 2
CMakeFiles/Makefile2:2069: recipe for target 'programs/qt_wallet/CMakeFiles/BitShares.dir/rule' failed
make[1]: *** [programs/qt_wallet/CMakeFiles/BitShares.dir/rule] Error 2
Makefile:654: recipe for target 'BitShares' failed
make: *** [BitShares] Error 2