Q3Private by design. Your images are processed locally in your browser. They are not uploaded to Q3 Labs, not stored on our server, and you can remove them at any time.
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Press Ctrl+V (Cmd+V on Mac) to paste an image from your clipboard.
JPG, PNG, WebP, GIF and AVIF (where your browser supports it). Up to 20 images, 52.43 MB each.
How to check image dimensions
- Add your image. Drag it onto the upload area, choose it with the button, or paste it from your clipboard.
- Read the results. The width and height in pixels appear alongside the aspect ratio, orientation, pixel count, format and file size.
- Copy what you need. "Copy image information" puts a clean text summary on your clipboard, ready to paste into a brief, ticket or email.
- Clear when you're done. Removing an image releases it from your browser's memory. Nothing was ever sent anywhere.
What image dimensions mean
A digital image is a grid of tiny coloured squares called pixels. Its dimensions are simply how many pixels wide and how many pixels tall that grid is. A 1920 × 1080 image has 1,920 columns and 1,080 rows, so 2,073,600 pixels in total.
More pixels means more room for detail, but pixel dimensions don't say how big the image looks. On a screen, that depends on the display. In print, it depends on how many pixels are used per inch. The same image can look small on a large monitor and sharp on a phone.
Image dimensions vs file size
Dimensions measure the picture; file size measures the file. A 4000 × 3000 photo saved as a well-compressed JPEG might be a few megabytes, while a smaller image saved as an uncompressed bitmap can be far larger.
- Dimensions are in pixels (width × height).
- File size is in bytes, shown here in KB and MB using decimal units (1 KB = 1,000 bytes), with the exact byte count beside it.
- Reducing dimensions usually reduces file size, but so does better compression. If a file is heavier than it should be, the Image Compressor can shrink it in your browser.
What is aspect ratio?
Aspect ratio describes shape rather than size: the proportion of width to height. It is calculated by dividing both dimensions by their greatest common divisor. 1920 × 1080 reduces to 16:9, 1080 × 1080 to 1:1 and 1200 × 1600 to 3:4. The decimal form (width ÷ height, for example 1.78:1) makes ratios easy to compare.
Orientation follows from the same numbers: wider than tall is landscape, taller than wide is portrait, and equal sides make a square. When an image is resized without keeping its aspect ratio, it is stretched, squashed or cropped, so keeping the ratio in mind avoids distortion.
How image resolution works: pixel dimensions vs DPI/PPI
"Resolution" is used loosely. For screens it usually means pixel dimensions. For print it means pixel density: pixels per inch (PPI) or printer dots per inch (DPI). Pixel density is the pixel dimensions divided by the physical size, so it cannot be worked out from the pixels alone.
For example, a 3000 × 2000 pixel image printed 10 inches wide has 300 pixels per inch; printed 20 inches wide, it has 150. The image file hasn't changed, only the size it is printed at. Files can carry a DPI value in their metadata, but it is frequently just a default label and doesn't change how many pixels the picture contains. That's why this tool reports pixel dimensions and does not present a DPI figure.
Common image dimensions
There is no single "best" image size. The right dimensions depend on where the image will be used, how large it appears and how sharp it needs to look. These are common examples you'll see, not platform requirements:
| Dimensions | Aspect ratio | Commonly used for |
|---|---|---|
| 1920 × 1080 | 16:9 | Full HD screens, video frames and widescreen hero images. |
| 1280 × 720 | 16:9 | HD video frames and smaller widescreen graphics. |
| 1080 × 1080 | 1:1 | Square images, often used for social posts and profile pictures. |
| 1200 × 630 | 40:21 (about 1.91:1) | A common size for link-preview (Open Graph) images. |
| 1080 × 1350 | 4:5 | A portrait format commonly used for social feed posts. |
| 1080 × 1920 | 9:16 | Full-screen vertical images and stories-style formats. |
| 800 × 600 | 4:3 | A classic size for older screens, thumbnails and small web graphics. |
Platforms and ad networks update their recommended sizes from time to time. Always confirm the current requirement on the platform itself before you produce final artwork.
When knowing image dimensions helps
Website images
Knowing an image's real dimensions helps you match it to the space it fills in your layout. An image far larger than the space it displays in wastes bandwidth, while one that is too small looks soft on high-density screens.
Social media
Platforms crop and resize uploads to their own layouts, and their recommendations change over time. Check the platform's current guidance, then use this tool to confirm your file matches the size and aspect ratio you're aiming for.
Blog images and thumbnails
Consistent proportions make a blog feel tidy. Checking that every featured image shares an aspect ratio stops thumbnails from being cropped unpredictably.
Profile images
Profile pictures are usually displayed square or in a circle. A 1:1 aspect ratio avoids awkward cropping, and a minimum size keeps them sharp on large screens.
eCommerce product images
Product pages look best when every image shares a size and ratio. Checking a batch of images at once shows you which ones don't match before you upload them to your store.
Presentations and digital ads
Slides and ad networks usually specify exact or minimum sizes. Confirm your creative meets the size in the brief before you submit it, and check the network's own current requirements.
Private, in-browser image checking
The tool reads your file with your browser's own image support. The image is not uploaded, there is no server-side processing, and Q3 Labs never sees it. The file names, image contents and dimensions are not included in any analytics. Because the tool relies on your browser to decode each image, the formats it can measure depend on your browser: JPEG, PNG, WebP, GIF and BMP are widely supported, AVIF works in current browsers that can decode it, and if a format can't be decoded you'll be told rather than shown a wrong answer.
Curious what else is hiding in a photo? The Image Metadata Viewer shows embedded EXIF and location data, and the Reverse Image Search helps you find where else a picture appears online.
Frequently Asked Questions
Explore more
Once you know your image sizes, shrink heavy files with the Image Compressor, turn a logo into a set of icons with the Favicon Generator, make a stand-in image of any size with the Placeholder Image Generator, or preview how a page's share image looks with the Open Graph Preview. Need a scannable code for a print design? Try the QR Code Generator, and when you write the captions and alt text to go with your images, the Word Counter keeps them to length. Browse all of our free tools, or see how our web design and UX team and web development services can help with images and performance on your own site.
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- Placeholder Image GeneratorCreate custom placeholder images with your own size, text and colors, and download them as PNG, JPEG or WebP.
- Image Metadata Viewer & RemoverView EXIF and image metadata, then create a cleaner copy in your browser.
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