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 file by dragging it into the drop zone or clicking to browse.
- 2Adjust the quality slider to balance file size and visual fidelity (optional).
- 3Click Download to save your converted file.
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. Choose between quality-based compression (adjust a slider) or target-size compression (specify an exact file size like 100 KB or 1 MB). The tool iteratively adjusts quality to hit your target as closely as possible. Supports JPG, PNG, WebP, AVIF, and BMP. Batch mode lets you compress multiple images at once.
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.
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.
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.
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