Feerebu

Studio

Load an image, set the recipe, and the page re-encodes it through a canvas and tells you exactly how many bytes came out. Every number on this screen is measured from a real encode — nothing is estimated, predicted or rounded up into a claim.

Drop an image, paste it, or browse

JPEG, PNG, WebP, GIF, BMP and AVIF are read if your browser can decode them. The file is opened with the File API and drawn to a canvas — it is never uploaded anywhere.

Result preview

File inspectorread from the original bytes

Recipe

Size

Width (px)

Height (px)

Keep the aspect ratio

Fit mode

Halve in steps when shrinking a lot

Orient & crop

0°

Flip horizontally Flip vertically

Apply the EXIF orientation found in the file

Crop to a box

X

Y

W

H

Trim the uniform border

Tolerance (0–64)

Pad to an aspect ratio

Ratio

Pad colour

Adjust

Grayscale

Brightness 100%

Contrast 100%

Saturation 100%

Blur 0 px

Sharpen 0%

Blurring before a lossy encode genuinely costs fewer bytes, because there is less high-frequency detail to store. The quality curve on the Analyse page will show you by how much, measured rather than claimed.

Colour

Reduce to a fixed palette

Colours

Dither

Median-cut quantisation, then nearest-colour mapping. With Floyd–Steinberg dithering the error from each pixel is pushed into its neighbours, which usually looks better at 16 colours and usually costs more bytes in a PNG. Both effects are measurable on the Analyse page.

Matte for formats with no alpha

JPEG cannot store transparency. Any transparent pixel is composited onto this colour before the encode, so you choose the background instead of getting whatever the browser defaults to.

Watermark

Draw a text watermark

Text

Position

Colour

Size 4% of the width

Opacity 70%

This is a watermark you asked for. Nothing this app produces is watermarked by the app itself, on either plan.

Encode

Output format

Quality 80%

Target size (KB)

Re-encode automatically when I change something

Compare

The original on the left of the handle, the re-encoded result on the right. Drag anywhere on the image. The byte counts under it are the real sizes of the two files, not a percentage anybody guessed.

Analyse

Everything here is a measurement of an encode that actually happened on this machine. The quality curve encodes your image once per quality step and reports the byte count each one produced; the bake-off does the same across formats. Nothing is modelled.

Pixel accuracy of this encode

Difference map

Quality curve

Format bake-off

Format × quality matrix

Luminance histogram

Colour census

Transparency audit

Metadata report

Batch

One recipe across every image in the queue. Each file is decoded, transformed and encoded in turn, and the table below is filled in from the real byte counts as they come back — a row appears only after that file has actually been encoded.

Queue

Run

Output name pattern

Tokens: {name} the original name without its extension, {ext} the new extension, {w} and {h} the output pixel size, {q} the quality, {i} the position in the queue.

Results

Bytes saved per file

Delivery

The markup that puts this image on a page, written from the sizes this app actually produced. Every width in a srcset here corresponds to a file that was encoded and measured, so the numbers in the attribute are not a promise you still have to keep.

Recipe library

A recipe is every setting in the Studio — size, orientation, crop, adjustments, colour, watermark, format and quality — saved under a name you choose. It holds no image: recipes are small, portable and safe to share, and the picture stays on your machine.

Save the current recipe

Name

Saved recipes

Workspace

One file holding every saved recipe, the recipe currently in the Studio and this session's encode log — everything this app knows about your work, not one view. It carries no image data.

This session's encodes

About & plans

What this app does, what it cannot do, and where the line between the two plans falls.

How it works

What this browser can encode

What it will not do

Free and Student Boost

Media Optimizer