Hi,
If you are using NAV 2018, you can take inspiration how image of customer is stored on customer card.
In background there is a field of type Media in Customer table. (Just like you have field in your table, just change its type to Media).
Then there is a page 785 Customer Image that keeps this image have functions to load image or change image or take image at runtime. You can use functions just like in that page.
After that attach this subpage to your main page.
