In my tireless efforts to inform and entertain you, I find myself wrangling a lot of pictures for posts here on CoM. And now that many people are coming at us from Retina-screened devices, we try to use big pictures whenever we can. But how big is a picture?
Clicking the image and tapping the spacebar will give you a preview, but it won’t give you the image’s pixel dimensions. Not unless you install QuickLook plugin qlImageSize.
Written by Mac developer Nyx0uf in order to scratch an itch of his own, qlImageSize replaces the filename of the QuickLooked image with its dimensions in pixels. Currently I have the Finder view of my desktop to show the dimensions under a picture’s thumbnail, but often this info takes a short while to show up.
If you like Nyx0uf’s free plugin, you might like Code Line’s SneakPeek Photo even more. It costs just $10, and will show you everything about your photo right there in the QL view. It gives you the full EXIF data of the image, as well as a histogram, GPS coordinates, camera data and even a loupe to check the picture close up.
I use it all the time, and miss it it greatly when I’m on a Mac without it installed.
Source: Brett Terpstra