Garmin won't read downloaded gmapsupp.img file

I downloaded a map of eastern Canada and US from openstreetmap onto the desktop in the last week. I extracted (unzipped) the file. I removed the old Garmin folder from my SD card and created a new Garmin folder on it. I copied the unzipped gmapsupp.img file from my desktop to the newly created Garmin folder on the SD card. BUT the file does not show up under maps and Garmin is not reading it. The only thing listed under map info is CN North America NT NA 2010.10 which I assume is the original map (in internal memory) that was on the Garmin when I purchased it. Even if I remove the SD card this map is still listed and appears to be working. This isn't the first time I have used openstreetmap to download maps to my Garmin but it is the first time that I have been unable to get it to work. No error messages show up on the PC or the Garmin at any time.

My unit is a Garmin Nuvi 1490 and I am using windows 10.

Any help would be greatly appreciated.