A lot of things get stripped in the html component. Not everything is supported. But it’s not documented. I had a similar issue but with other elements and attributes:
It seems that flexbox is supported. So perhaps you can add a div of the same size in the html component as the image. And then add the image in there with width=“100%” ?
You did try the width attribute on the img tag I presume?
You’ll have to try a lot of things before you get something exactly right and even then in might not be possible. Perhaps someone from Retool knows if width on img is supported or a workaround.
The fact that there’s no documentation on what is supported makes it very difficult to find a solution.