It is very thankful if we can have 'Select File’ option in Custom Connector so that it can be used with binary to update the Business Central picture field.
It could be update Item Picture using binary with ‘Select File’ option from Postman.
Using custom connector to update:
Even it shows ‘204 No Content’ returned code but the image isn’t loaded in BC Item Picture with message ‘No preview available for media content type application/octet-stream’ because JSON doesn’t allowed to pass the raw binary value as following.
Postman also can’t use raw binary to update the Item Picture, which is same result we got when using custom connector.