Are the images I pick uploaded anywhere?

No. There is no code here that sends an image over the network, and results still come out offline.

How do I keep the aspect ratio from breaking?

Leave the aspect lock on and type one side; the other follows the original ratio.

What pixel size do cm and mm become?

The length in inches times the DPI. 10cm at 300 DPI is 1181 pixels.

What DPI should I use?

300 for a print shop or photo print; 150 for a document from a home printer.

Can I make an image larger than the original?

You can, but it will not get sharper. The list shows both resolutions side by side.

Does the file size come down too?

Smaller dimensions bring the size down. To meet a fixed size limit, use Image Compressor.

How many images at once?

Thirty per run, up to 30MB each.

Does GPS or capture information survive into the result?

No. A new file is built from the pixels, so capture information has no way in.

The saved photo is not in my gallery.

Look at the button label. Save to Photos puts it in the gallery; Download sends it to the Files app first.

Which formats can it read and write?

It reads five formats, including HEIC and AVIF, and saves as JPEG or WebP.

If I do not like the result, is my original changed?

No. The result is a separate new file.

Image Resizer — set width and height in pixels, cm or mm

Drop images here, or

Unit Width px Height px

Lock aspect ratio (give one side and the other follows the original) Save as

Advanced

Quality 90%

How do I resize an image?

Drop the images here or pick them with Choose files.
Press a common size or type the width and height. With the aspect lock on, one side is enough.
Check the original and the result in the list, then save.

What pixel dimensions should I use?

Use the largest size the destination accepts. The values people reach for most are in the Common sizes buttons.

Do cm and mm give the right print size?

Yes. The → N px shown beside the field is exactly the pixel size of the file that comes out.

A tool that only takes pixels makes you convert the print size by hand, and a wrong conversion usually shows up only after printing. Here you type cm or mm and read the → N px before you save.

Keeping the proportions

With the aspect lock on, give one side and the other fills from the original. The error against the original ratio is at most one pixel.

Can I make several images the same size at once?

Yes, up to 30 at a time with the same settings. To force exactly the same width and height on every image, turn the lock off and type both values.

Common questions

Are the images I pick uploaded anywhere?: No. There is no code here that sends an image over the network, and results still come out offline.
How do I keep the aspect ratio from breaking?: Leave the aspect lock on and type one side; the other follows the original ratio.
What pixel size do cm and mm become?: The length in inches times the DPI. 10cm at 300 DPI is 1181 pixels.
What DPI should I use?: 300 for a print shop or photo print; 150 for a document from a home printer.
Can I make an image larger than the original?: You can, but it will not get sharper. The list shows both resolutions side by side.
Does the file size come down too?: Smaller dimensions bring the size down. To meet a fixed size limit, use Image Compressor.
How many images at once?: Thirty per run, up to 30MB each.
Does GPS or capture information survive into the result?: No. A new file is built from the pixels, so capture information has no way in.
The saved photo is not in my gallery.: Look at the button label. Save to Photos puts it in the gallery; Download sends it to the Files app first.
Which formats can it read and write?: It reads five formats, including HEIC and AVIF, and saves as JPEG or WebP.
If I do not like the result, is my original changed?: No. The result is a separate new file.