@demihualian So "origin" should contain the text you want to post, along with {img url.goes/here} {alt description goes here}

So with the example you gave, something more like this:

{
"origin": "Test {img #imgUrl#} {alt #altText#}",
"imgUrl": "https://i.imgur.com/cVgKZCX.jpeg",
"altText": "Alt text goes here"
}