Reducing the size of SDCard images for distribution
Using USBImageTool or Etcher or whatever to make a copy of a working SD Card so that it can be shared produces a file the size of the SD Card. There are several problems with this: 1. The file is HUGE and so difficult to upload, download, distribute to others. 2. If the partition was setup at the full size of the SD Card, then another SD Card which is advertised as the same size, may actually have slightly less space and therefore not accept the image. E.g. Not all 8GB SD Cards actually have the same amount of free space. You might start with one that has 7.8GB free, and find the next one you purchase has 7.78GB free.
Obvious solutions are to not expand the Xilinux partition as far as the SD Card will accept. e.g. use only 7.5GB of an 8GB card. But then you still have a 7.5GB image when you may have only used 4.5GB.
Ideally, we would like to use larger SD Cards, have lots of space to work, then produce an image that does not include the freespace and show users how to increase the partition size when we send them the image, just as we did with Xilinux in the first place.
Resizing the image appears to be possible, but difficult. Any advice on best / easyist methods of doing that would be appreciated. Also it would seem like incremental updates of a large image should be possible, by only storing the parts of the .img file which change.