If you have an .img file then you can't just copy that file to A:. In fact, you don't even need to format a disk if you are writing an .img file to it, because the img contains the format. The .img file contains a sector-by-sector binary image of what the disk should look like, and you need a piece of software that will read those sectors from .img file and write them to directly to those disk sectors at a very low level.
Imagine a disk is like a new sheet of blank white paper. You can write stuff on it but it'll be disorganized. Formatting the disk is like adding a margin and lines - the margin takes up space that you can't write in, but it, with the lines, helps organize the stuff you write on there. The .img file already contains the disk format (margin and lines etc) so it's like you're taking a sheet of lined/margin paper full of crappy 80's song lyrics (the .img file) and trying to fit it onto your new sheet of paper that you just put a margin and lines on (your new formatted disk). You cannot overlap the margin on your new sheet, so the sheet with the song lyrics won't fit (this is the 17kb). What you need to do is just paste the sheet of song lyrics directly on top of your new sheet, lining up the edges so it fits. Doesn't matter if your new sheet had margin/lines or was blank, it's all overwritten - and now it's just crappy 80's song lyrics.
Getting back to reality... There are many options. RaWrite is one I've used in the past.
http://www.netbsd.org/~martin/rawrite32/
http://www.chrysocome.net/rawwrite
I currently don't have a modern PC with IDE any more so I use a GreaseWeazle to connect via USB - this creates a very low-level connection (does not 'mount' the disk, but allows image files to be read and written). https://decromancer.ooo/greaseweazle/ If you have a floppy drive that you can format and store data on then you don't need this - I just mention this for folks who have older disk drives that you can't buy USB version from Amazon. I can connect my 5.25 to my modern PC and use GW to write img files to it, then those disks work on my vintage PCs.
Regarding Cyclic Redundancy Checks... Back in the days where floppy disks were the norm and hard disks were a luxury... it was just understood that some floppy disks arrived with bad sectors. The CRC error sounds like that. DOS will recognize bad sectors, mark them, then avoid them when storing individual files, but an img file does not allow the flexibility of just putting data somewhere else on disk. A disk with bad sectors cannot be used on an img file because the img file dictates exactly where to store the data on the disk, and if that is on top of a bad sector then so be it. Bzzz Bzzz Bzzz Error.. If you have a floppy disk that gives you a CRC error when writing an img file to it then I would do a full format of the disk (not a quick format, which skips the exhaustive sector-by-sector checks) and then run CHKDSK. It will tell you if it found bad sectors. Any bad sectors? Mark the disk. It's still ok for files, just not disk images.
