The short version
Look for pixel dimensions in the file's properties or open the image in a checker. Width × height gives total pixels, while simplifying width:height gives aspect ratio.
What matters most
- Use pixel dimensions, not the on-screen zoom level.
- A file can have the right ratio but insufficient pixels.
- For print, divide pixels by intended PPI to estimate inches.
How to apply it
- Open the original file rather than a messaging-app preview.
- Read width and height from properties or an image checker.
- Calculate megapixels and simplified ratio.
- Compare against the final screen dimensions or desired print size.
Reference table
| Value | How to calculate | What it tells you |
|---|---|---|
| Dimensions | Read width × height | Exact pixel grid |
| Megapixels | width × height ÷ 1,000,000 | Total pixel count |
| Aspect ratio | simplify width:height | Frame shape |
| Print inches | pixels ÷ PPI | Potential physical size |
Use exact dimensions and units in production notes; familiar labels can describe more than one standard.
Common mistakes to avoid
- Checking a thumbnail instead of the source file.
- Reading only file size in MB.
- Assuming 72 DPI metadata limits screen quality.
Continue with the right tool
Use a calculator to check the numbers against your own source and destination instead of relying on a generic preset.
Related guides
What Is Image Resolution? Pixels, Dimensions and Detail Explained
Understand image resolution, pixel dimensions, megapixels and print density without confusing them with aspect ratio or file size.
Images and photosHow to Resize an Image Without Losing Quality
Resize images cleanly by preserving aspect ratio, choosing an appropriate resampling method and avoiding unnecessary recompression.
Images and photosHow to Resize an Image Without Pixelation
Prevent blocky edges and soft detail by understanding source pixels, enlargement limits, resampling and final viewing size.
Frequently asked questions
Can a browser check an image locally?
Yes. AspectRatioZ reads the selected file in your browser; the image does not need to be uploaded.
Where is resolution shown on Windows or macOS?
Both systems show pixel dimensions in file information or properties panels.
What resolution is enough?
Enough means at least the final displayed pixel size, or the desired print inches multiplied by target PPI.