Cause: Unable to export BPMN2 process to PNG file.
Consequence: The browser which populates after clicking on the "Export to png" feature cannot find the file which needs to be created in pdf format.
Fix: Both share and download are now functional for png and pdf. Fix was implemented in designer master and 6.0.x branches.
Result: The required BPMN2 process can now be exported to PNG file.