I have just figured out how to share a album via LR. I did this specifically for the download option for my client, they wanted to pick and choose which files to download. When I tested it my original file was 2.1mb when I downloaded it it was 650kb. Why is the downloaded file smaller than the original? Is there anywhere to change that setting to original size? I could not see anything.
The downloaded file is usually always smaller that the original in physical size-on-disk terms because the download is in jpeg format, and some element of jpeg compression will be applied to that file (the effectiveness of which can also be affected by the actual image content). However, that's not the measure you should be using, you should be more concerned with the actual pixel dimensions of the downloaded file, which should be the same as the original. Is that the case?
That's curious. 2048 used to be the default size for downloaded files from LrWeb, but that has since changed and as far as I can see the default is now "full size". As the owner of the album, you have several other options when downloading images from your own shared album via your LrWeb portal, one of which is a 2048 size. How exactly are you testing this aspect??
If you want to send me the link via a private message I'll happily test to see what size I get.