Enable libpng and libjpeg support by default, added graceful error handling
Enable libpng and libjpeg support by default, added graceful error handling

cvjena/cn24,mylxiaoyi/cn24,mrgloom/cn24,mylxiaoyi/cn24,cvjena/cn24,cvjena/cn24,mrgloom/cn24,mrgloom/cn24,mylxiaoyi/cn24