I'm using FM13 Advanced (Mac) to develop a solution. I copied my original file, experimented with different background images for a layout, and also did some other development. The file size difference between my original file and the one with background image experimentation is significant...more than I would expect from the other development I did. 

 

As a test, I saved off another version of the file using the "Compacted copy (smaller)" option, but this had minimal effect. I also wrote a script to flush cache to disk, but this had no effect on file size. 

 

So I'm wondering...is it possible that FM has cached the unused background images I experimented with somewhere in the file, and if so, is there a way to purge them?

Yes,  and that's why you really don't want to use those kind of graphics / non-native FM objects.  Especially if you are going to use the layouts over slow connections (WiFi, 3G/4G, internet,...)

Thank you for the insight!

 

In this case, the background image is a third-party form (originally supplied as a PDF) that must be printed as-is. My experimentation was around the best rendering of the third-party form to optimize file size/printed readability (TIFF, JPEG, PNG, etc.). I'll plan on exploring other options as you suggest.

 

In the meantime, is there a way to get under the hood of my FM file and purge any unneeded/unused cached images?