toolready. Image Resizer

Image Resizer

Resize images by pixels, percent, or fit-to-box. Lock aspect ratio.

What this does

Drop an image, tell the tool how big you want it, and download the result. There are three ways to describe the target size, because people arrive with three different problems:

  • Pixels (W × H) — the default. Type an exact width or height. Lock ratio is on, so editing one field recalculates the other and nothing gets stretched. Untick it if you genuinely want a distorted image.
  • Percentage of original — a slider from 1% to 200%, starting at 50%. Handy when you just want "half size".
  • Fit longest side — enter one number (default 1920) and the longer edge is scaled to it, portrait or landscape. This is the one to use when a site says "images must fit within 1920px".

The panel shows the resulting dimensions before you commit. Decode, scale and encode all happen on a canvas inside your browser tab; the file never travels to a server.

How do I resize an image to specific dimensions?

  1. Drag a file onto the dashed box or click it to browse. The name, size and current pixel dimensions appear.
  2. Leave Resize by on Pixels and type your width; the height fills in automatically while Lock ratio is ticked.
  3. Optionally pick an Output format and nudge the quality slider.
  4. Click Resize & download. The file is saved as the original name plus the new dimensions, e.g. banner-1200x630.jpg.

Which output format will I get?

The default is Same as input, which keeps PNG as PNG and WebP as WebP; anything else — JPG, HEIC, GIF, BMP, AVIF, SVG, ICO — comes out as JPG. If you need transparency from a GIF or SVG, choose PNG or WebP explicitly, because JPG has no alpha channel and transparent regions will be filled. GIFs are resized as a single still frame; animation is not preserved. HEIC photos from an iPhone are decoded through a WebAssembly module of about 2.7 MB that downloads the first time you use one.

What does the quality slider do?

It only appears for lossy outputs (JPG and WebP) and runs from 10 to 100, defaulting to 92. PNG ignores it. Lower numbers mean smaller files with more compression artefacts; 92 is a safe high-quality setting for a resized master. If your real goal is a small file rather than a particular size, the compressor lets you watch the byte count change live as you drag the slider.

Can I make an image bigger?

Yes, up to 8192 pixels on either side — the percentage slider goes to 200% and the pixel fields accept values up to that cap. Upscaling cannot invent detail; the browser's high-quality smoothing keeps edges from looking blocky, but a 400-pixel thumbnail blown up to 4000 will be soft. Ask for more than 8192 and the preview shows the size it will actually produce, labelled "capped from" your request.

What are the limits?

  • One image at a time, up to 50 MB.
  • Accepted inputs: PNG, JPG, WebP, AVIF, GIF, BMP, SVG, ICO and HEIC/HEIF.
  • Output is clamped to 8192 × 8192; requests above that are reduced, not rejected.
  • Metadata such as EXIF is not carried into the output, because a canvas re-encode only writes pixels. If you want that behaviour on purpose, the EXIF viewer shows you what is being dropped.

Need to change the framing rather than the size? Use the crop tool; to change only the format, use the converter, which also handles batches.