When saving files using the znap format using the form that is saved in a zip file, the saved zip file appears to not be using any compression, resulting in an output file that is the same size as if it was uncompressed. I can confirm that compression is possible by decompressing the znap.zip file and then re-compressing it, and the file size is decreased fairly dramatically (from around 160MB to 90MB in my case).
I suspect that the files are being placed into a zip file using “store” instead of a specific compression level. Is this the intended behavior?