Oh, ok. I thought of it some time after I mentioned it here. But as for me, it looks very strange and unusual to see rasterized images in Figma, but I understand that in some cases it could be better in order to set a high level of performance and opportunities for stamps designer.
But as it is shown on a screenshot it looks nearly awful especially when it has a maximum size, so maybe it would be a good idea at least to make them better quality.