Yep, that’ll work too. You can set any width/height you wish you do not necessarily need to use the shortcode values. Personally, I really can not see a difference between the small image @100 and the larger image scaled down with CSS. Perhaps that is simply due to my display. It’s not cheap or low end but is not a HiDPI either as it has a pixel density of about 110 PPI. If you are viewing on a Mac Pro or a high end tablet/phone which has a higher pixel density then scaling down a larger image in CSS would make a little difference. I did dev a feature to specifically support HiDPI images but disabled it for now since it does cause the directory to load slower as it has to create multiple images for the browser to swap in the most relevant based on the device/browser. The slowest part is that the browser has to download multiple images. I do revist this from time to time so at some point I am sure I will enable this feature again.