Guide · Error message
"Resolution
too low".
The wording changes with the platform, file too small, low print quality, low resolution image, but it always means the same thing, and there are only three ways out.
Diagnose the file, right now
Drop the rejected image. The browser reads it on your machine, nothing is uploaded.
What the platform actually checked
Nothing mysterious: it divided your file's pixel width by the ordered width in inches, and compared the result to its threshold. Usually 300 DPI for a fine art print, 150 for a poster, sometimes 100 for a large canvas.
density obtained = pixels ÷ inches
An image 2000 pixels wide ordered at 16 inches gives 125 DPI. Below a 150 threshold, it is rejected. The same file at 8 inches gives 250 DPI and passes. A file is never too small in the absolute: it is too small for the size asked.
The file's DPI tag plays no part in this. You can set it to 300, to 72, or delete it, and the check returns the same answer. Why.
The three ways out, without illusions
1. Order a smaller size
Free, immediate, and often the right call. A 3000 pixel file holds 10 inches at 300 DPI. The calculator gives the exact figure.
2. Accept a lower density
A print hung and viewed from three feet only needs 150 to 200 DPI. If the platform lets you override the warning, do it knowingly. The distance scale.
3. Upscale the file
The only route that keeps the size you wanted. Mind the method: plain interpolation will pass the automated check, which only counts pixels, and give you a soft print. A neural upscale rebuilds material, and that shows on paper. Up to about ×4 the reconstruction stays credible; beyond it the network invents more than it rebuilds.
The common wordings, decoded
| What you read | What it means |
|---|---|
| Resolution too low | pixels ÷ size < platform threshold |
| Image too small for this size | same calculation, other words |
| Low print quality warning | a warning, the order still goes through |
| Low resolution image | usually triggered below 150 DPI |
| File must be 300 DPI | enough pixels for the size, not the tag |
| File dimensions do not match | this one is the aspect ratio, not resolution |
That last case is a different problem: your image may be large enough but in a ratio the format does not sell. A square pushed into 3:4 loses a quarter of its surface.
Keep the size you wanted
The workshop upscales in your browser, crops to the ratio print shops sell and writes the file at 300 DPI. Its interface is in French for now.
Read next: converting 72 to 300 DPI, check a file.