Compress an image without losing the details you need

Start with the purpose of the image

A full-resolution camera photo is often unnecessary for a small web illustration. Conversely, a receipt or screenshot may need enough pixels to keep small characters readable. Choose the dimensions for the task instead of using the lowest possible quality value.

For example, fitting a 4000 × 3000 photo inside 1200 × 1200 with its aspect ratio preserved produces a 1200 × 900 image in FileFlow’s Contain mode. Cover mode instead fills the square by cropping edges. These are different editing decisions, not just compression settings.

Choose a format for the content

Try JPG or WebP for photographs. PNG can be a better choice for transparent artwork and graphics with sharp edges. Compatibility also matters: use a format your destination can open.

FileFlow’s PNG output is lossless at the encoding stage and ignores the lossy quality slider. To make a PNG smaller, reducing unnecessary dimensions or choosing a different suitable format may help more than moving the quality control. Lossless encoding does not undo damage in a source image that was already compressed with losses.

Compare quality settings with an actual example

For a photo, try JPG at 70% quality as a starting experiment. Compare it with the original at normal display size, then look more closely at faces, sky gradients and fine texture. Try a higher value if important details become visibly damaged.

If you need a particular upload limit, inspect the resulting file size after each attempt. The quality percentage does not predict the output size, and there is no guaranteed fixed compression ratio. Avoid repeatedly recompressing the previous result; use the original for each comparison.

Why the compressed file can be larger

An already optimized input may have little room to shrink. Browser encoding settings, metadata handling, a different output format or the image’s content can produce a larger result. A small JPG converted to PNG will often grow because PNG stores that decoded image differently.

ZIP is also not a substitute for choosing useful image dimensions and encoding. Photos are already compressed, so packing them in an archive may barely reduce their size. It is still useful for grouping files.

Keep a reversible workflow

Download the candidate, compare its size and appearance, and keep it only if it meets your needs. Preserve the original separately. On a phone, start with a small batch rather than selecting all photos at once.

File size limits are not a promise that every device has enough memory. Decoding creates pixel data in memory, which can be much larger than the source file. Close unused tabs or reduce the image dimensions if a large operation fails.

Try it in FileFlow

1. Choose the image.
2. Select an output format and quality; try JPG or WebP for photos.
3. Convert, compare file sizes and inspect detail before keeping the download.

Try a photograph at 70% JPG quality, then increase quality if faces or text look damaged.

Limits and privacy

Up to 100 MiB per file, 20 files and 200 MiB per operation. Images and resize output are limited to 25 megapixels. Smaller batches may be needed on phones. Re-encoding can change metadata and does not guarantee a smaller file.

Processing runs in your browser. File contents, names and recognized text are not sent to FileFlow servers or analytics. Loading the site and OCR models still uses the network. Keep your original until you have checked the download.

This guide page has no file picker and does not process documents. The tool opens in a separate website document. Live advertising is currently disabled.

Frequently asked questions

Related reading

• PNG to JPG: choose the right format and avoid transparency surprises