A ceiling, and a floor
Most size tools stop at “under 50 KB”. Indian upload portals often say “between 20 and 50 KB”, and a file under the minimum is rejected just like a file over the maximum. So this page takes both. Quality opens on “Fit under a size” with a 50 KB ceiling; add a minimum and the result is checked against it too.
The search is real: each candidate quality is a full-size encode of your picture with your background and your edge settings, and the one kept is the highest quality that lands at or under the ceiling. Because the figure is measured, the button can print it.
When quality alone cannot do it
- Over the ceiling at quality 1: a large or noisy picture. The page offers the largest pixel size that fits at quality 60, found by encoding.
- Under the floor at quality 100: a small or very plain picture. The page offers the smallest enlargement that reaches the minimum. Enlarging adds no detail, and the page says so; check the form accepts the new pixel size.
- Inside the range: done. The note under the field says which quality was used and how many encodes it took.
Questions about kilobytes
- Why is my JPG under the minimum KB?
- Because a small, simple picture does not hold enough detail to fill the space, even at quality 100. A 140 × 60 signature on white can come out at six or seven kilobytes however it is encoded. The tool says so with the figure and offers the honest way up: a larger pixel size, found by encoding until quality 100 reaches the floor. It never pads the file with junk bytes.
- Is 50 KB 50,000 or 51,200 bytes?
- Here it is 51,200: one kilobyte is 1,024 bytes, and the page says so under the field. Most upload portals count the same way. If yours counts in thousands, set the ceiling a couple of kilobytes lower and the file will satisfy both readings.
- Why did the picture get smaller to fit?
- It only does when you ask. If even quality 1 is over the ceiling, the page tells you the figure and offers to find the largest pixel size that fits at quality 60, by encoding at several sizes. Press it and the new size goes on the undo stack like any other change.
- How is the quality chosen?
- By bisection over real encodes at full size: quality 100 first, then quality 1, then halving the gap until the highest setting at or under the ceiling is found — seven or eight encodes at most. The size on the Save button is the size of the file it saves.
- Does fitting a size change the background?
- No. The matte, the edge repair and the size search are separate decisions. The colour under the transparent pixels is whatever you chose, and the size search runs on that composite.
Next steps
- PNG to JPG for online formsKB range, pixels and DPI set together from a form's published rule.
- Signature PNG to JPGInk cropped and put on white, in the 10–20 KB range.
- PNG to JPG high qualityWhen there is no size limit and the picture matters more.
