How to check an image’s size
The tool above does it in one drop, but here’s the whole flow — and the manual ways, for when you just need the numbers:
- 1
Drop the image in
Drag a file onto the box above, click to browse, or paste from your clipboard. JPG, PNG, WebP, GIF, AVIF, HEIC, and SVG all work, and nothing is uploaded.
- 2
Read its real metadata
You get the exact pixel dimensions, the reduced aspect ratio, the format, and the file size in under a second — no spec sheet to memorise.
- 3
Check the per-platform fit
Every platform surface gets a Fits / Warn / Fail verdict, with the reason — wrong shape, too small, wrong format, or over the file cap.
- 4
Fix and re-check
Crop, scale, or compress as the verdict says, then drop the new version back in to confirm it passes before you post.
On a Mac: select the file in Finder and press Space for Quick Look — dimensions show under the preview — or right-click → Get Info for size and format.
On Windows: right-click in File Explorer → Properties → Details for dimensions and size, or read them in the status bar in details view.
On iPhone: open the photo, swipe up, and the resolution and file size sit at the bottom. iPhones shoot HEIC by default — you can drop that straight in here, but convert to JPG before uploading to some desktop apps.
On Android: open it in Google Photos, then the menu → Details for resolution and size.
What the platforms do to a wrong-sized image
Every platform recompresses what you upload, and a mismatch costs you in one of three ways. Too small and it gets upscaled, which adds blur. Wrong shape and it gets cropped to fit the surface — usually through the part you wanted seen. Over the file cap and the upload fails or strips the image silently. Checking before you post saves the re-edit cycle every time, and once the verdict points at a fix, our image resizer re-crops one source to every platform size in the browser. For the reasoning behind the ratios, the guide to image sizes covers why they barely move even as the pixels do.