What does an image compressor do?
An image compressor shrinks a photo or graphic's file size by discarding visual data that is hard to notice or by re-encoding it more efficiently. A 6 MB phone photo can often drop to 500 KB or less with no visible difference at normal viewing sizes. Everything here runs directly in your browser using the Canvas API - your images are never uploaded, and the whole process happens in memory on your device.
Quality presets vs. target file size
Use quality presets when you want a quick, predictable result: High keeps almost all detail, Balanced is a good default for most photos, and Small favors file size over fidelity. Pick Custom to fine-tune with the slider.
Use target file size when you have a hard limit to hit - an email attachment cap, a CMS upload limit, or a specific KB/MB budget. The tool searches for the highest quality setting that still lands at or under your target, so you get the best possible result within the size you set.
Choosing an output format
Leave the format on Keep original to compress without changing the file type. Otherwise:
- JPEG - smallest files for photos, no transparency support. Best for photographs and complex images.
- WebP - typically 25-35% smaller than JPEG at the same visual quality, and supports transparency. Supported by all modern browsers.
- PNG - lossless, keeps every pixel exact. Larger files, no quality slider, best for screenshots, logos, and graphics that need pixel-perfect edges.
When a PNG without transparency is detected, the tool suggests switching to WebP, since it usually compresses flat-color and photo content noticeably smaller without visible quality loss.
Reading the before/after preview
Click Preview on any row after compressing to see the original and compressed image side by side, along with the exact size change. This makes it easy to confirm a setting is not too aggressive before downloading the full batch.
How to compress images
- Drop one or more images onto the drop zone, or click Browse files.
- Pick an output format, then choose a quality preset or enable target file size.
- Click Compress. Each row shows its status as it finishes.
- Preview a result, then download it individually or grab everything as a ZIP.
Common uses
Website images
Large hero images and product photos slow down page loads. Compress to WebP at 70-80% quality for a big size reduction with no visible loss.
Email and upload limits
Many forms and email providers cap attachments at a few MB. Use target file size mode to land safely under the limit without guessing at a quality value.
Batch cleanup
Drop an entire folder of screenshots or camera photos, apply one setting to all of them, and download the whole set as a ZIP in one click.
Frequently asked questions
Will compressing reduce image quality?
Some quality loss is inherent to lossy compression (JPEG and WebP), but at 70% quality and above it is typically invisible on a normal screen. PNG output is lossless, so quality is never affected - only file size may not shrink as much.
How does target file size mode work?
The tool repeatedly tries different quality levels and narrows in on the highest one that still produces a file at or under your target size, so you get the best quality possible within your limit.
Why is my compressed file larger than the original?
This can happen with already-compressed images, very small files, or simple graphics with few colors. Try a different output format, or keep the original if compression is not helping.
Are my images uploaded anywhere?
No. Every step - loading, encoding, and previewing - happens in your browser. Nothing is sent to a server.
Is there a limit to how many images I can compress?
No limit. Files are processed one at a time so memory stays low even with large batches.