Just to clarify, since your first two questions are about the download zip mechanism: Since version 0.6.0, download and zip is done entirely in browser. This is more effective than first creating and caching the zip file on server. See the link for more details
Quanti #1 Can you download all folders as a single .zip file as well?
This is not currently an option. I might consider it, but it would be very fragile depending on the amount of content in all your folders. If done in browser, all files would need to download into browser, and we would have to use PHP to create a data file of all files ... both these processes could be slow, and could fail. If done on server, we would still need to use PHP to create a data file of all files in all dirs, but additionally, the zip process might fail (memory) or timeout (depending on the resources of server vs the amount of files).
It's technically possible, but it could easily be slow and unreliable, certainly for 1GB+ file structures.
Quanti #2 How long does browser zip preparation take for larger folders? Like gigabyte range.
As of version 0.6.0, there is no delay, since files download_dir is set to
browser and will simply start downloading into browser. Desktop browsers should be able to handle 1GB+, but not all mobile devices ... And download speed would depend on client connection vs server connection of course.
Quanti #3 Is there a way to have a download button placed a bit more accessible? I'd like to share my images to clients via this route instead of sending them just a .zip folder. And I'm afraid some of them won't find the download button via the little icon. It really should be dead simple for them.
This has been requested earlier. As you have noted, all folder-options are currently stacked away under a single dropdown menu. I think I will be adding options to add these buttons individually in the topbar, making them more obvious. For this feature, you would have to wait ...
Quanti #4 Is there a way to have some sort of download log?
This question is a bit unspecific. Do you mean for single-file downloads? Or for folder zip downloads? You could log folder zip download by setting
zip and then loggin each download via PHP ... Either by adding an entry to database, or simply appending to a TXT or JSON file. Would not be too complicated.
You can log really log single-file downloads, because this is done directly in browser
<a download></a>. The only way to achieve something like this, would be 1. Use your server logs, or 2. Add Google Analytics and set it up to track clicks on specific links, or 3. Set option load_files_proxy_php to true, and then use PHP to log them (similar as above).