[x2t] Add image extensions to GetFormatByExtension
[x2t] Add image extensions to GetFormatByExtension

ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core,ONLYOFFICE/core