fix broken img refs big data slide deck

docs/topics/big_data_intro_for_researchers.html

@@ -129,7 +129,7 @@
    - handle failures
  - for really BIG DATA may not be possible 
 
-<img src="img/split-apply-combine-daigram.png" width="400px">
+<img src="../img/split-apply-combine-daigram.png" width="400px">
 
 
 ---
@@ -183,7 +183,7 @@
 - code can be R, Python,  SQL, or Scala (a version of Java)
 - you can interact using Notebook, or with a remote connection
 
-![Sorting with Spark from theRinSpark](img/example_spark_operation_smaller.png)<br>
+![Sorting with Spark from theRinSpark](../img/example_spark_operation_smaller.png)<br>
 *Sorting distributed data with Apache Spark, from Mastering Spark with R*
 
 
@@ -208,7 +208,7 @@
 
 Two videos linked Link to Video introduction and walk through from Doug Krum, MSU IT Services Data Architect in our session
 
-![Azure Data Bricks Architecture](img/databricks_arch.jpg)
+![Azure Data Bricks Architecture](../img/databricks_arch.jpg)