Varying subfigure width

Discussed in https://github.com/quarto-dev/quarto-cli/discussions/1817

^{Originally posted by jpmorr August 11, 2022}
When dealing with a single image it's quite simple to vary the image width in the standard markup:

![Nice picture](image.jpg){#fig-img1 width=60%}

I'd like to do something similar when using a subfigure to have a little more fine gained control over some I'll fitting figures generated elsewhere.

::: {#fig-specimen_comp layout-ncol=2}

![Nice picture](image.jpg){#fig-img1 width=60%}

![Nice picture2](image2.jpg){#fig-img2}

Comparison between two samples
:::

However, I've noticed that the width attribute is completely ignored in the subfigure, setting to 10% or 90% does not change the size of the subfigure. I don't want to change the width of the column as the caption text should be equal width in this case. Is it possible to change the width of the figure, much like in latex you can set a figure to be [width=0.75\textwidth]?

Obvious solution is to make a copy of the figure I want to resize and crop it to fit better, but I like the latex solution of just changing the size.

Read discussion #1817 and reproduce the supplied Quarto Markdown example with different subfigure width values. Trace how the subfigure layout handles image width compared with a standalone image. Done means the width setting changes the subfigure image without changing the column or caption width, with behavior matching the requested LaTeX-style control.