Hiding an Element when generating via API from template

When generating a video from template via API, it is possible to change to manually setting image urls etc.
But is it possible to hide images, too.
I need to hide / remove this image for the current scene:

"variables": {
"bild2": {
"name": "bild2",
"type": "image",
"properties": {
"url": "https://www.testsite.com/images/test/img1.jpg"
}
},
...

Would I do it so (doesn't work, just tested):

"variables": {
"bild2": {
"name": "bild2",
"type": "image",
"properties": {
"url": ""
}
},
...

Or so:

"variables": {
"bild2": {
"name": "bild2",
"type": "image",
"properties": {
"url": null
}
},
...

Thanks for help! :-)