Issue with Images on the UICanvas in the nft-wall-example-scene

[Frans]

I'm using https://github.com/decentraland-scenes/nft-wall-example-scene
to show images that will have a unknown size to me.
They get weirdly stretched on the Canvas UI. The last pixels from the right side and/or bottom get stretched to fill the area.
It seems like the example got around this issue by making all the images 1024*1024, by adding white space to them.

Is there away to just have a image just naturally fill the width or height of the defined space, like you would with CSS.