Image compression: formats, quality, and dimensions

Fluximage compresses your images server-side and converts them to the format you choose. Every image you upload is re-encoded at the quality level you set, with the option to cap its dimensions before output. The result is a smaller, web-ready file you can download individually or as a ZIP.

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Output formats

Choose one format per batch. All images in the batch are converted to that format. WebP is the most broadly supported modern format and delivers the best balance between compression and compatibility. Use it for most web projects. AVIF achieves even higher compression than WebP but requires a more recent browser. Choose it when you need the smallest possible files and your audience uses up-to-date browsers. JPEG is the safe fallback for systems that don’t support modern formats—email clients, some CMSes, and legacy apps. PNG uses lossless compression. The quality slider has no effect on PNG output; the file is always encoded at maximum fidelity. Use PNG when you need pixel-perfect results or transparency.

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Quality

The quality slider controls how aggressively Fluximage compresses each image. It applies to WebP, AVIF, and JPEG output.

• Range: 40–100
• Default: 82

Lower values produce smaller files with more visible compression artifacts. Higher values preserve more detail but result in larger files. Values below 60 are noticeable on photos; values above 90 produce files that are close to lossless in size.

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Dimension limits

You can optionally set a maximum width, maximum height, or both. Fluximage resizes any image that exceeds these limits before compressing it.

• Aspect ratio is always preserved — the image is scaled down proportionally.
• Images smaller than your specified dimensions are never upscaled.
• Leave both fields empty to keep images at their original dimensions.

These limits apply to the entire batch. If you need different sizes for different images, process them in separate batches.