Added checks to the `outputFormatType` method, to be sure that the type and format parameters will not be in a state which could cause problems when saving the thumbnails.
Added checks to the `outputFormatType` method, to be sure that the type and format parameters will not be in a state which could cause problems when saving the thumbnails.

iFrankWu/thumbnailator,voole/thumbnailator,DavidGOrtega/thumbnailator,sunwei415/thumbnailator,linpeixun/thumbnailator,wenhe666/thumbnailator,mirszhao/thumbnailator,zhaochenxi0518/thumbnailator,westei/thumbnailator,wangda/thumbnailator,puth/thumbnailator,mystijk/thumbnailator,bpzhang/thumbnailator,cjmcn-sh/thumbnailator,maleck13/thumbnailator,sateeshb/thumbnailator,tasermonkey/thumbnailator,sisihuisi/thumbnailator,passerby4j/thumbnailator,yehwang/thumbnailator,herohenu/thumbnailator,icq112771720/thumbnailator,codingEcho/thumbnailator,PandaCanFly/thumbnailator,AascisB/thumbnailator,sinisterrook/thumbnailator,mxgsa/thumbnailator,ghosta3/thumbnailator,indra7/thumbnailator,vfishv/thumbnailator,gigaZhang/thumbnailator,xuyanxiang/thumbnailator,kapa76/thumbnailator,Jframeye/thumbnailator,tmxdyf/thumbnailator,coolshou/thumbnailator,nickleo/thumbnailator,ldx007/thumbnailator,atrijitdasgupta/thumbnailator,joyepay/thumbnailator,jasonqu/thumbnailator,mecnet/thumbnailator,liyiguang/thumbnailator,feexon/thumbnailator,zhway9909/thumbnailator