Why won't the resizer let me make an image 15000 px wide?
Because the output has two limits: 12000 px for any side, and 50 megapixels for the whole image, sizes that browser canvases handle reliably. A 15000 px width breaks the side limit, and even 10000 by 6000 breaks the pixel limit at 60 megapixels. For very large print files, ask the print shop what resolution it really needs, which is often lower than you think.
The two limits and their messages
The tool draws the new image on a canvas inside the browser, and every browser caps the size of that canvas and the memory it grants. So there are two tested limits, each with its own message under the width or height field:
- Side limit: 'A side can be at most 12000 px.' It appears if you type a width or height above 12000.
- Pixel limit: 'The output is above the tested limit of 50 megapixels.' It appears when each side is fine but the two multiplied exceed 50 million pixels.
15000 × 5000: rejected by the side limit.
10000 × 6000: each side is allowed, but the output is 60 megapixels, so the pixel limit rejects it.
12000 × 4000 and 8000 × 6000: both accepted, at 48 megapixels each.
The input has similar limits: files up to 40 MB and up to 50 megapixels. Large sizes that are accepted can still fail on a phone with little memory, so use a computer for very big files.
Do you really need 15000 px?
People usually ask for numbers like this for large prints, such as a roll-up banner or an exhibition board. But a large print is viewed from a distance and does not need the resolution of a photo held in the hand. Here is an 85 by 200 cm roll-up:
At 300 dots per inch: 10039 × 23622 px, rejected by the side limit.
At 150: 5020 × 11811 px, which is 59.3 megapixels, rejected by the pixel limit.
At 100: 3346 × 7874 px, which is 26.3 megapixels, accepted.
The right resolution is the print shop's call, not ours, so ask before you prepare the file. If it asks for more than the limits allow, the file needs design software made for large-format print, not a browser tool.
What to do now
- Read the message to see which limit you hit.
- For the side limit, bring the larger number down to 12000 or less with the ratio lock on.
- For the pixel limit, reduce the width or height until the two multiplied are 50 million or less.
- Remember that going above your original's size adds no detail, and a warning will say so.
If you only need part of a huge image, crop it first in the Image cropper and then resize it in the Image resizer, which keeps the output within the limits.
Common questions
Why 50 megapixels in particular?
It is the size the tool was tested to handle reliably in browsers; going beyond it risks the page running out of memory or freezing.
Can I still download when the size is rejected?
No. No file is produced while the message shows, and the download button stays disabled until you correct the number.