Compress Images Online — Free, No Upload Required
Reduce image file size with quality or target-size compression — entirely in your browser.
How It Works
- 1Upload your image by dragging it into the drop zone or clicking to browse.
- 2Adjust the quality slider or target size to control how aggressively to compress.
- 3Click Download to save your compressed image.
About Image Compressor
Need to reduce your image file size for email, web upload, or social media? This tool compresses your images entirely in your browser — no upload to any server, ensuring your photos remain completely private. Choose between two compression modes: quality-based compression, where you adjust a slider to control the output quality, or target-size compression, where you specify an exact file size like 100 KB or 1 MB and the tool iteratively adjusts quality to hit your target as closely as possible. Supports JPG, PNG, WebP, AVIF, and BMP input formats. Batch mode lets you compress multiple images at once, saving time when optimizing an entire gallery or folder of photos. Whether you need to meet a file size requirement for an online form, optimize images for faster website loading, reduce attachment sizes for email, or fit photos within social media upload limits, this compressor handles it all. The compression algorithm uses binary search to find the optimal quality level, giving you the best possible image quality within your size constraint.
From the blog
- 11 min read
How to Compress Images Without Losing Quality
A practical guide to image compression: what JPG quality really means, when to resize before compressing, and how to hit a target file size without obvious artifacts.
- 9 min read
HEIC vs JPG: Which Format Should You Use?
HEIC files are half the size of JPGs at the same quality, but compatibility is uneven. Here's when to pick each — and how to convert without losing detail.
Frequently Asked Questions
How does image compression work?
This tool re-encodes your image as a JPEG with adjustable quality. Lower quality means smaller files but more compression artifacts. In target-size mode, the tool uses binary search to find the optimal quality that produces a file at or under your target size.
What's the difference between quality mode and target-size mode?
Quality mode lets you set a specific quality level (e.g., 80%) and see the resulting file size. Target-size mode lets you specify an exact file size (e.g., 100 KB) and the tool automatically finds the best quality that fits within that limit.
Can I compress multiple images at once?
Yes! You can drag and drop multiple images and they will all be compressed with the same settings. Each result shows the original and compressed size.
Is my file uploaded to a server?
No. Transmute processes everything locally in your browser using JavaScript and the Canvas API. Your files never leave your device — there is no server, no upload, no cloud processing.
Related Tools
Compress Image to 100 KB
Compress any image to under 100 KB — perfect for email attachments, government forms, and job applications with strict file size limits.
Compress Image to 200 KB
Compress any image to under 200 KB — ideal for web uploads, document attachments, and platforms that cap file size at 200 KB.
Compress Image to 1 MB
Compress any image to under 1 MB — great for social media uploads, messaging apps, and email attachments with reasonable size caps.
Image Resizer
Resize images to exact dimensions or social media presets (Instagram, Twitter, LinkedIn). Lanczos3 resampling preserves sharpness.