a few - I hope - quick questions

ReSizing images in blocks
here still on the adam theme

the theme offers sizing variables in the block (image and slider blocks)
but each time I adjust them they change the Resolution of the image
and then stretch the image to the width of the text or to the viewport (as per the options button)

the images are coming from the page folder (so very helpful)
not from the shared image browser
if that makes a difference

but that dosent seem like the expected use of the sizing variables
(or I'm just not understanding what the intended purpose is?)

I would like to set the max size of the image to appear under the text
300 width for instance
(and i'm assuming that the smaller size then would be cached for speed?)

then my hope is for the image appears centered or justified under the text block (no option for this. but no prob)
but not so large - and regular for all blocks set to the same settings

THE SAME problem is on the light/dark (but I did not test as much)
but in light/dark it is with cropping? not just resolution as in adam?

the only solution i find is to pre-size the images
before import
which kinda kills the usefulness of the width and height settings for image and slider blocks (?)
the width and height seem to be computing something... but I dont know what
I get different numbers depending on the image size - but not the true image sizes - more like a rounded off size?

so yeah
sorry I'm confused

clarification on the best practices for development the toolchain
for better or worse it seems that almost ever theme is using a different framework and thus tool chain
adam - ?
bulma - bulma
bootstrap - bootstrap
light/dark - ?

adam seems to be set up to use .less files and glup to produce the adam.min.css?
or should I be using composer?
or is there some gui that makes this easier? (im on a mac)

if I was to fork the adam theme (you give very good instructions on that - thanks)
what sort of toolchain for development would you recommend? for adam theme...
or what are you are using?

thanks again
G