TidyToolsMaking something smaller is free. Making it bigger is not.
Scaling an image down is genuinely lossless in the sense that matters: the detail you keep is real detail, averaged from pixels that were actually there. A 4000-pixel photo reduced to 1000 pixels looks superb, and it is the single most effective thing you can do to a file that's too large.
Going the other way, nothing can add detail that was never captured. Enlarging a 200-pixel image to 800 asks the software to invent 15 pixels for every one it has, and it invents them by smearing the neighbours. The result is bigger and softer, never sharper. This tool will do it if you ask — sometimes a specification demands a minimum size and soft is better than rejected — but it warns you on the row, because the honest answer is usually to find a larger original.
A worked example
A marketplace wants square listing photos, exactly 1000 × 1000, and yours came off a phone at 4032 × 3024 — landscape, and nowhere near square.
Choose Exact size, type 1000 by 1000, and leave it on Crop to fill. Each photo is scaled until it covers the square and the overflowing sides are trimmed away, centred, so you get a full-bleed 1000 × 1000 image with no borders. Switch to Pad to fit instead and the whole photo survives with white bars top and bottom. Both are exactly 1000 × 1000; they differ in what they sacrifice.
The three ways to force a shape
- Crop to fill — scales until the image covers the target and trims the overflow from the edges, centred. Nothing is distorted, but some of the picture is gone. This is what almost every website does to your profile photo, and it's the right default.
- Pad to fit — scales until the whole image fits inside the target and fills the leftover space, white for JPG and transparent for PNG. Nothing is lost and nothing is distorted, but the subject ends up smaller with bars around it.
- Stretch — forces the image into the target shape by squashing it. Faces go wrong immediately. It exists because occasionally you need exact pixels on something like a texture or a banner where distortion doesn't read, but for photographs it is almost always the wrong answer.
If the target shape happens to match the original, all three do the same thing and the choice doesn't matter.
Pixels, print sizes and "300 dpi"
A common source of confusion: an image file has no physical size. It has a pixel count, and dpi is only a note attached to it saying how densely to print those pixels. Changing dpi without changing the pixels changes nothing about the image at all.
So when a print shop asks for 300 dpi, what they actually need is enough pixels: multiply the inches you want by 300. A 6 × 4 inch print needs 1800 × 1200 pixels. Set that here and you have what they asked for, whatever the dpi tag says.
Passport and visa photos
Worth being blunt: pixel dimensions are the easy part of those requirements and rarely the part that gets rejected. Head size as a proportion of the frame, background colour, expression, glasses and shadows are all specified, they differ by country, and no resizer can check them. Use this to hit the pixel size the upload demands, and check the actual rules on the issuing authority's own page.
Frequently asked questions
Are my images uploaded anywhere?
No. Resizing happens in your browser with the same image engine that draws web pages. There is no server, no account and nothing stored. Load the page once, go offline, and it still works.
Will resizing reduce the quality?
Scaling down looks excellent — the tool uses high-quality smoothing and the result is genuinely sharp. Scaling up cannot add detail that was never there and will always look softer than the original, which is flagged on the row when it happens.
How do I resize without cropping anything?
Either use "Pad to fit", which keeps the whole picture and fills the leftover space, or use "Longest side" or "Percentage", which keep the original proportions and never crop.
Can I resize a batch of images at once?
Yes. Drop in as many as you like; the same settings are applied to all of them and you can take the results individually or as one ZIP. "Longest side" is usually the most useful setting for a mixed folder.
How do I get 300 dpi?
By supplying enough pixels. Multiply the print size in inches by 300 — a 6 × 4 inch print needs 1800 × 1200 pixels. The dpi number stored in a file doesn't change the image; only the pixel count does.
Does it keep transparency?
Yes if you save as PNG, including the padding added by "Pad to fit". JPG cannot store transparency at all, so transparent areas become white.
Is there a limit, or a watermark?
Neither. Resize as many images as you like and nothing is added to the output.