Exact pixels without stretching
Most size boxes on forms and shop listings are exact: 1200 × 1200, 1080 × 1350. A PNG rarely has those proportions. Fit keeps the whole picture and fills the leftover strips with the matte colour, the same colour that goes under the transparent pixels, so the padding and the background are one decision. Fill covers the box and crops; pick which of nine anchor points the crop keeps.
The resize happens before the edge repair and the matte, so the fringe around a cut-out is judged and fixed at the size it will be seen, not at a size nobody will look at.
Limits of this page
- Enlarging adds no detail. It is never done silently, and the page says so whenever it happens.
- Stretch changes the proportions of everything in the picture. It is there because some forms demand an exact box; it is never the default.
- There is no free-hand crop here yet. Fill crops to the box around an anchor; a crop tool is planned.
Questions about resizing
- What is the difference between Fit, Fill and Stretch?
- Fit puts the whole picture inside the box without distorting it, and the leftover strips become the matte colour — a JPG has to be a full rectangle. Fill covers the box and crops whatever overflows, around the part you choose to keep. Stretch makes the picture exactly the box, changing its proportions; the page says so.
- Will it make my picture bigger?
- Only if you ask. The long-edge sizes above your PNG's own are not offered until you switch on “Allow enlarging”, and an exact box larger than the picture says plainly that enlarging adds no detail.
- How do I get a size in centimetres?
- Use Print size under the Size tab: type the width in cm or inches and the DPI, and the page sets the pixels that size needs and writes the DPI into the file. 21.0 cm at 300 DPI is 2,480 pixels.
- Why does a big reduction look sharper here than in some tools?
- Because a reduction of more than two times is done in halvings first and then one final pass to the exact size. A single drawImage over a big reduction leaves the result to whichever shortcut a browser's resampler takes; halving first gives much the same result everywhere. The page says which method it used.
- Which sizes are the quick picks?
- 1,080, 1,200, 1,600, 2,048 and 4,096 pixels on the long edge. 1,080 is the largest width Instagram says it keeps; the rest are common web and print sizes.
Next steps
- PNG to JPG 300 DPIWhen the size is for print and the DPI has to be in the file.
- PNG to JPG in KBResized and still over the limit? Fit the kilobytes too.
- Batch PNG to JPGOne long edge for a whole folder.
