make the Mobile Responsive Images challenge more robust fixes #998
make the Mobile Responsive Images challenge more robust fixes #998

FreeCodeCamp/FreeCodeCamp,jonathanihm/freeCodeCamp,pahosler/freecodecamp,FreeCodeCamp/FreeCodeCamp,otavioarc/freeCodeCamp,raisedadead/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,pahosler/freecodecamp,HKuz/FreeCodeCamp,raisedadead/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,otavioarc/freeCodeCamp,HKuz/FreeCodeCamp,jonathanihm/freeCodeCamp