Check an image's size, format, DPI and print size

How to use Image Info

1. Choose an image (JPEG, PNG, WebP, GIF, AVIF, BMP, TIFF, ICO, SVG or HEIC).
2. Press Inspect.
3. Read the results: Dimensions, Format, File size, Megapixels, Aspect ratio, Bit depth, Colour type, Transparency, Progressive (JPEG), Animated (GIF, WebP, PNG), Embedded DPI, EXIF orientation when the photo is stored rotated, and Bits per pixel (compressed).
4. Check the table Print size at common resolutions for 72, 150, 200, 300 and 600 DPI, in centimetres and inches.

What it does and when to use it

Use it before uploading to a form with rules (“at least 600 × 600 px”, “JPEG only”), before sending a photo to a print shop, or when a file behaves oddly and you suspect it is not what its name says. It also answers everyday questions such as whether a PNG has a transparent background, whether a GIF is animated and how many frames it has, and whether a JPEG is progressive.

To change what you find, use the Image Resizer for pixel size, the Image Converter for format, or the DPI Checker to write a new DPI value without touching the pixels.

How it works

The file’s bytes are read in a Web Worker on your device. The tool identifies the format from its signature, then reads the header fields where each format stores width, height, bit depth and colour type. DPI comes from the JPEG JFIF or EXIF block or the PNG pHYs chunk. If the header has no size, the tool decodes the image to measure it. The print table is pixels ÷ DPI, times 2.54 for centimetres.

Worked examples

Figures computed with the tool’s own formulas.

A 12-megapixel camera photo. For 4000 × 3000 px the tool reports 12 MP and an aspect ratio of 4:3. If the file is 3,000,000 bytes, Bits per pixel is 2. The print table includes:

So at 300 DPI it fills a sheet a little larger than A4, which is 29.7 × 21 cm.

A phone screenshot. For 1170 × 2532 px, the sides share no small ratio, so the aspect ratio shows as 0.462:1, and megapixels as 2.96. At 300 DPI it would print only 9.91 × 21.44 cm.

A social media portrait. 1080 × 1350 px is reported as 4:5.

Limits and tips

• Transparency for PNG comes from the header; JPEG never has it.
• The tool reports; it never changes the file.
• Several files can be checked one after another.