Figuring out optimal image size

I am trying to conserve on server space and would like to bring in my images at 100% size. How do I figure out what size these image placeholders are?

https://nnninvestmentadvisors.com/off-market-properties-3/?preview_id=3341&preview_nonce=b1a5369958&_thumbnail_id=-1&preview=true

Hi, the link you posted is not visible (it’s a draft)…

But you can see the size of images on any web page if you use an extension like this one (Web Developer Toolbar): https://chrispederick.com/work/web-developer/ It’s available for Chrome and Firefox.

After you install it, you just have to click in the toolbar on the Images tab, then on “Display Image dimensions”: