Application forms say things like minimum 600 × 600 pixels, maximum 200 KB, JPG only. Print shops ask whether your photo is big enough for a poster. Your computer's file properties answer part of this, but not the print size, and not whether a file named photo.jpg is really a JPG. This tool checks everything in one table.
The files are read in your browser and are not uploaded.
How to use it
- Drop one image or many images at once.
- Read the table. For each file it shows the real format, width × height in pixels, megapixels, file size in KB or MB, aspect ratio, the DPI stored in the file (or not set), the print size in centimeters at that DPI and at 300 DPI, and whether the image has transparency.
- Use the copy button to copy the table as text, for example to paste into an email or a support request.
What the columns tell you
Real format is detected from the file's content, not its name. Every format starts with a recognizable signature, so the tool can tell when a file called photo.jpg is actually a HEIC or a PNG, and it flags the mismatch. Renaming a file never converts it; Changing a file extension is not converting explains why. To get a real JPG from an iPhone photo, use HEIC to JPG.
Megapixels is width times height. A 4000 × 3000 photo has 12 million pixels, or 12 MP.
Aspect ratio is the shape, such as 3:2, 4:3 or 16:9. It matters when a form or platform expects a certain shape.
DPI is only a printing instruction stored in the file. If it says not set, the print size simply depends on the DPI you choose when printing. The 300 DPI column shows the size at which the image prints sharply: a 4000 × 3000 photo gives about 33.9 × 25.4 cm.
Transparency shows whether the image has see-through areas. If you convert such a file to JPG, those areas get filled with a solid color.
Matching a form's requirements
| The form asks for | Check this column | Fix it with |
|---|---|---|
| A maximum file size | File size | Compress to a target size |
| Minimum or exact pixel dimensions | Width × height | Resize image |
| A specific shape, such as square | Aspect ratio | Crop image |
| JPG only | Real format | PNG to JPG or HEIC to JPG |
| A specific DPI | DPI | cm to pixels and DPI |
Leave a small margin under size limits. Some systems count 1 KB as 1024 bytes and others as 1000, so a file that looks like exactly 200 KB on one system may count as slightly more on another.
Frequently asked questions
Why does the DPI column say not set?
The file does not store a DPI value. That is common for screenshots and images from websites, and it does not affect quality. The print size then depends on the DPI chosen when printing.
Why does the tool say my JPG is another format?
The file's content belongs to a different format, usually because it was renamed rather than converted. Some programs open it anyway, but forms and older software may reject it. Convert it properly to fix this.
Why is the file size different from what my computer shows?
Systems count differently. Windows divides by 1024 per step, while macOS uses 1000, so the same file can show slightly different KB or MB numbers.
Are my images uploaded to check them?
No. The files are read in your browser, and only the information in the table is shown on your screen.