The overflow CSS shorthand property sets the desired behavior when content does not fit in the parent element box (overflows) in the horizontal and/or vertical direction.
Overflow hidden is one of those features that seems like it should work in a very specific way, but it comes with a few strange side effects that can be incredibly frustrating and hard to fix.
It would be much more efficient to just clip the image before hand instead of asking the browser to create a complicated mask each time the image loads.
Getting the mask to be the right shape can be complicated. The much easier option is to erase the background on the image. You can do this in Photoshop or use one of the free online tools. When the background is replaced with transparency, this layout becomes very simple.
the bottom left corner of the image or container element could be clipped with something like this could be used to clip the right, bottom and left but clear enough room for the heads while maintaining the rounding.
FYI as well, CSS was mostly cleaned up as part of Interop 2023. So if this is something that folks have been avoiding for compatibility reasons. That is not a huge concern anymore.
I think part of the issue we are having here is not knowing what the original image the OP is using looks like. ie are we only clipping off part of the persons right arm or are we also clipping legs?