Image Compressor & Resizer
Resize and compress JPG, PNG and WebP images with a live preview of the file size you save. Images are processed on a canvas inside your browser, so nothing is uploaded and the originals on your device are never modified.
Resize before you compress
Most oversized images are large because nobody resized them, not because the compression setting was wrong. A phone photograph is commonly around 4000 pixels wide. Displayed in an article at 800 pixels, that means the visitor downloads roughly twenty-five times more pixel data than their screen will ever use. Decide how wide the image will actually appear and resize to roughly twice that, which keeps it crisp on high-density screens without waste. Useful starting points are 1600–1920 pixels for a full-width banner, 800–1200 for an in-article image, and 200–400 for a thumbnail.
Picking a format
Format choice can change file size by a factor of ten. WebP typically produces files 25–35% smaller than a comparable JPEG and supports transparency, making it the sensible default for anything staying on the web. JPEG remains the most universally compatible choice and suits photographs that will be emailed or opened in unknown software. It has no transparency at all. PNG is lossless and keeps transparency, which makes it right for logos, screenshots and anything containing text. It is the wrong choice for photographs: saving a photo as PNG is the most common way to accidentally make a file larger instead of smaller.
Finding the quality setting by eye
Quality sliders are not percentages of visual fidelity, and there is no universally correct number. Start at 80 and compare the result against the original at the size it will actually be displayed, rather than zoomed in. Compression artefacts appear in predictable places. Watch smooth gradients such as skies, which develop visible banding; areas of flat colour, which become blotchy; and the edges around text, which develop a faint halo. Busy, detailed photographs hide compression well and often tolerate 65 or lower.
What cannot be undone
Reducing dimensions permanently discards pixels. Shrinking a 4000-pixel photo to 800 and later needing it large again means the detail is genuinely gone, and enlarging the small copy will look soft. Lossy compression is equally one-way. Always keep your originals somewhere and treat compressed versions as disposable exports. Compressing an already-compressed JPEG stacks artefacts on artefacts, so always start from the original file rather than a previous export.
Quick tips
- Exporting a transparent PNG as JPEG fills transparent areas with white, not black.
- Do all cropping and colour correction first, then compress once as the final step.
- Re-encoding through the browser generally strips EXIF metadata, including GPS location.
- If a change saves only a few percent, it is not worth the quality cost.
Are my images uploaded to a server?
No. Images are processed entirely inside your browser using the HTML canvas. Your files never leave your device, which makes this safe for private or sensitive photos.
Which output format should I choose?
WebP usually gives the smallest file at the same visual quality and supports transparency. JPEG is the most universally compatible but has no transparency. PNG is lossless and keeps transparency, but produces much larger files.
Why did my PNG get bigger instead of smaller?
PNG uses lossless compression, so re-encoding a photo as PNG can increase its size. For photographs, choose JPEG or WebP. PNG is best for logos, screenshots, and graphics with flat colour or transparency.
Does resizing reduce quality?
Reducing dimensions discards pixel data permanently, so enlarging the result later will look soft. Always keep your original file and treat the compressed copy as an export.