Canvas II MC 327HW MacOS Catalina

Trying to get my SD Cards to work on my Meural canvas II

Followed all instructions available . Created Folders on the suggested  SD card meural 1 meural 2  etc formatted on MacOS  - format   exFAT

Was told to create thumbnails 68x120 for vertical  - 120x68 for horizontal .

All Thumbnails must  then be formatted, as example :  Italy.Jpeg.thumb 

Sorry  not a Pro , but How do i create the thumbs and format them ??

Note: Earlier suggestions from the Netgear Community said to name each picture 

example : "italy.jpeg"  ( that failed, the canvas did read the Card but only displayed the name / Text , but the not the picture , aka black screen .!!!

I contacted Customer Service in the Phillipines , talked to at least  5 different expert Technicians

what resulted into completely resetting  ( erasing ) the whole canvas and me reloading  approx 2000 pictures back onto it !  Result : The screen is still 

Black when i try to load the SD Card !!

Positive note : I love this tool , have it for 3 Years , am a Film- maker and use it for daily display in my office , no other problem so far,  just too bad i cannot use the SD card .... any help out there for the not so savy ??   

PS Would be nice to have a detailed  step by step instruction manual 

to properly use the full features of the Meural II  , i got a handful  colleagues  into Meural Canvas , most of us are struggling with various issues !!

For now , if anybody needs help out there, i suggest to write or call Customer Service via Philippines ,get a Case#  AND  ask for Bella , she is a senior Supervisor TECH very  knowledgeable , patient

and reliable !! She sent me a basic instructions for the naming , unfortunately for me not detailed enough  !!!  

Thanks