This does not work, or I am doing something wrong. 🙁
Config File:
"optionImages" : {
"sizes": {
"hero": "(max-width: 1200px) 100vw, 1200px",
"smallImages": "(max-width: 749px) 100vw, 749px"
},
"dimensions": {
"xs": {
"width": 300,
"height": 200,
"group": "smallImages,hero"
},
"sm": {
"width": 480,
"height": "auto",
"group": "smallImages,hero"
},
"md": {
"width": 749,
"height": "auto",
"group": "hero"
},
"xl": {
"width": 1200,
"height": "auto",
"group": "hero"
}
}
}
Template File (use smallImages):

Browser html code. Displays all sizes. Not only the size of the group “smallImages”

Also the browser then uses the largest file – XL 1200 px and not SM 480 px