Image Resizer

Direct answer

Image Resizer redraws the originally selected static bitmap to a Canvas at the requested width and height. With the ratio lock on, changing 4000 × 3000 to 1200 pixels wide derives 900 pixels high. Every Generate action reads the original selection rather than the previous export, and a download appears only when the returned Blob MIME matches the requested PNG, JPEG, or WebP type.

Local file safety limits

Choose one GIF, JPEG, PNG, or WebP file no larger than 20 MiB. Width and height must each be 1–16384 pixels, decoded area must not exceed 16,777,216 pixels, and estimated working memory must not exceed 256 MiB. The browser validates the declared MIME, file signature, decoded bitmap, requested output MIME, and output dimensions.

Output limits

Canvas export can change metadata, EXIF, ICC profiles, orientation handling, animation, transparency, color, and lossy quality. Keep the original and inspect every downloaded output in its destination.

How to use this tool

1. Choose a file this browser can decode and confirm that source width and height are each between 1 and 16384 pixels.
2. Enter a target width or height. Keep the ratio lock for proportional output, or unlock it only when distortion is intentional.
3. Select PNG, JPEG, or WebP, generate once, then verify the preview, MIME type, pixel dimensions, transparency, and file size before download.

Worked example: 4000 × 3000 to 1200 × 900

Choose the 4000 × 3000 source, leave the ratio lock enabled, and enter width 1200. The derived height is 900. Confirm that the output summary says 1200 × 900 and that important text or faces still look sharp at the intended display size.

Dimension and repeat-operation boundaries

Source and output width and height must each stay within 1–16384 pixels. The derived side is checked after ratio calculation, so a setting that would produce 32768 pixels fails. Changing a parameter invalidates the old download; generating again still uses the original selected bitmap.

Encoding is a separate decision

JPEG and WebP quality values are browser encoding hints, not target byte sizes. PNG ignores that control. The tool checks the actual Blob MIME before naming the file; decode support, encoder results, transparency, color handling, and device memory remain browser-dependent.

What browser-local means here

The AIGClub resize handler has no application upload request and uses an object URL, Image, Canvas, Blob, and a download link. This statement does not claim that the whole page makes no network requests or that extensions, device software, metadata, EXIF, or ICC behavior are controlled.

Frequently asked questions