you can pass the logo from the back end, by using this example:
It's basically 3 steps:
1. create a JWT with the DID and the profile data (name, url, and profile image)
2. upload the self-signed JWT to IPFS
3. vc field just contains the IPFS hash
In step 1 the profile image should be an image url, in our case it is an IPFS url.
The VC field will be used to create a disclosureRequest: https://github.com/uport-project/uportlandia/blob/4ef0ebceaaf91f26ec16a4a92a74589869b677a8/src/server.js#L35