Here is some code on how to embed Base64 in HTML:
<img src="data:image/jpeg;base64,BASE64_STRING"/>
Since Chrome apps are now being deprecated. Download postman from https://dl.pstmn.io/download/latest/linux
Although I highly recommend using a snap
sudo snap install postman
tar -xzf Postman-linux-x64-5.3.2.tar.gz