I will play with the PartsList again tomorrow with fresher eyes, but I have yet to find these relationships (/ppt/slides/_rels/slideX.xml.rels)...
Let me ask a higher-level question: I have a "placeholder" image in a powerpoint "template" that I am loading with data on the fly.
What is the best way to replace an image in the pptx? I'm thinking that I need these mid-level relationships to tie the slide to the image part within the pptx, so I know which image to replace; I have not crossed the bridge of having to replace that image--will that be possible? Or is that even the best way?