Fixes problems when image format is !== to internalFormat
Fixes problems when image format is !== to internalFormat

We should clearly keep only one field for this.

gideonmay/osgjs,jmirabel/osgjs,jtorresfabra/osgjs,gideonmay/osgjs,kkuunnddaannkk/osgjs,hishamabdelrahman/osgjs,cedricpinson/osgjs,kkuunnddaannkk/osgjs,jtorresfabra/osgjs,cedricpinson/osgjs,jtorresfabra/osgjs,jmirabel/osgjs,kkuunnddaannkk/osgjs,hishamabdelrahman/osgjs,hishamabdelrahman/osgjs,cedricpinson/osgjs,jmirabel/osgjs,gideonmay/osgjs