How to transfer a map with w6j file ?

Hello everybody !
I have wrote this post : here, and the thank for Neil to answer me, but i am still can't do anything with this .Img file

when i open the img file (that i have found inside map folder) with Gmap tool the program make the mapset as "other data" and don't give me any details about the map

when i open the img file with ImgTool it gives me :"the file gmapsupp.img is not a valid garmin img file

i am sure this img is a valid file because i have only 1 map in my device and i have 1 img file in map folder

i have found a .w6j file with this name "gmapsupp.img.w6j" in map folder,

i want to transfer this map to my new device, but when i paste the .img file from the old device to the new one the map don't show, and there's no notification when i turn the new device on

i don't know what to do in real