I have some feedback on saving you bandwidth and us some download and site posting time.
For those of us who host elsewhere and make content changes we need to download and test either in the design and clean up stages or then later with content updates and changes, we don't need all the photo's and graphics zipped and sent back down, in fact after building 10 sites now with my admin processes to move the files to my hosting I find I have all the graphics and photos already in a folder in my desktop FTP account for the site, so it is no problem to either just leave them there or move them to the images folder you create and use, then upload to my hosting as needed.
I also find that I may see a very minor error on a site and need to go in change it then end up downloading the complete site files and needing to reupload all them to the hosting as not sure what in the package is really needed so the whole site still works .. so if you are able to break out what is zipped and downloaded to just what changed and needs to be zipped that would save alot of bandwidth for you and us. Here are some familiar options on a program I used for years ...
1) files changed from last download ( this is the one that always works for me)
2) whole site