Compressing an image without destroying readability

1. Identify what must remain legible

For a photograph, facial detail and edges may matter most. For a receipt, form or screenshot, small letters, numbers and thin lines are the critical content. Note the destination’s pixel dimensions and byte limit before making changes.

Keep the original untouched. Repeatedly saving an already compressed JPEG can accumulate artifacts around text and high-contrast edges.

2. Remove pixels the destination cannot use

Crop empty borders first. If the source is far larger than the display or upload requirement, resize it with the aspect ratio locked. Reducing dimensions usually saves more space than forcing a very low quality setting at the original size.

Do not upscale a small source before compression. More pixels will not restore missing detail and may create a larger, softer file.

3. Choose a suitable output format

JPG is widely compatible for photographs but has no transparency. WebP often produces a smaller photographic file at similar visible quality when the destination accepts it. PNG is useful for sharp graphics and transparency, but it may be much larger for photographs.

Browser canvas export removes embedded camera metadata and may change color-profile handling. Animated images become a single still frame. Transparent areas become white when exporting to JPEG.

4. Compress, measure and inspect

Use the highest quality that meets the real limit. A target-size search cannot guarantee success because dimensions and image complexity set a lower bound. If the result remains too large, return to the original, resize modestly, and try again.

• Check the measured output size against the portal limit.
• Zoom to 100% and inspect small text, signatures and high-contrast edges.
• Open the file in a second viewer before replacing or submitting anything important.