Free online CZI to PNG converter

Microscopy teams create PNG copies when reports, presentation software, web systems, or collaborators need a standard image instead of a ZEISS data container. A PNG is usually a rendered 2D view, so the original CZI must remain available for analysis and reprocessing.

What the CZI format is

CZI is the proprietary microscopy container format used by ZEISS ZEN software and ZEISS imaging systems. A .czi file can contain several scenes, fluorescence channels, Z-slices, time points, tile scans, pyramid levels, stage positions, calibration data, objective settings, and acquisition metadata.

CZI files are common in confocal microscopy, slide scanning, tissue imaging, cell imaging, and time-lapse experiments. ZEISS ZEN reads CZI directly, while Fiji/ImageJ can read it through the Bio-Formats importer.

What the PNG format is

PNG is a losslessly compressed raster image format supported by browsers, office software, operating systems, and image editors. It is appropriate for a single plane, a rendered channel composite, an annotated figure, or an overview image because it avoids JPEG compression artifacts.

PNG stores integer grayscale, RGB, or RGBA pixels, including 8-bit and 16-bit samples in the format specification. It cannot store a CZI's channel stack, Z dimension, time dimension, tile layout, calibration, or acquisition metadata as an equivalent microscopy dataset. PNG does not support floating-point pixel samples.

Convert a CZI file to PNG

For a quick export, upload the .czi file to the converter on 101convert.com, choose PNG, and download the result. This is suitable for a simple 2D image or a preview, but inspect the output carefully: a multidimensional CZI may require a choice of scene, channel, Z-plane, time point, or rendered composite that an automatic conversion cannot infer.

Do not upload patient data, unpublished results, or restricted microscopy data unless external transfer is permitted by the relevant institutional policy.

Export with ZEISS ZEN

1. Open the CZI file in ZEISS ZEN.
2. Select the required scene, channel or channel composite, Z-plane, time point, and region.
3. Set channel colors and display ranges only when exporting a presentation or publication rendering.
4. Use the version-specific export command, commonly under File → Export or an image context menu, and select PNG.
5. Choose the output size and bit depth where available, then verify the exported file against the selected view.

ZEN is the safest option for files containing ZEISS-specific scene layouts, tile scans, or display settings because it interprets the acquisition in its native environment. Menu names and available export controls vary by ZEN version and licensed module.

Export with Fiji and Bio-Formats

1. Install Fiji, which includes Bio-Formats.
2. Open Plugins → Bio-Formats → Bio-Formats Importer, select the CZI file, and choose the required series. A series often represents one scene, position, or acquisition region.
3. Select the required channel, Z-slice, and time point with the hyperstack controls.
4. For separate channel data, use Image → Color → Split Channels and export each required plane. For a display composite, configure the channels, then use Image → Type → RGB Color before saving.
5. Save the selected image through File → Save As → PNG, using names such as sample_c1_z005_t012.png.

A normal PNG represents one raster image, not a Z-stack or time series. Export planes as numbered files, or use File → Export → Image Sequence when separate PNG files are required for many planes.

Bio-Formats also includes bfconvert for automated workflows. Use bfconvert -help for the installed version's series, plane, and filename-pattern options, and test one representative CZI before batch conversion.

Quality and compatibility caveats

Lossless PNG compression does not make the export lossless. Cropping, downsampling, channel mixing, color rendering, contrast changes, and conversion from 16-bit or floating-point source data can remove or alter information before PNG compression occurs.

A displayed fluorescence composite is normally an 8-bit RGB rendering. Its pixel values reflect the selected LUTs, display range, gamma, and channel blending rather than the original intensity values. For quantitative work, retain the CZI and export individual source channels at their available precision; confirm the resulting bit depth with the receiving software because many general-purpose viewers display only 8-bit images reliably.

PNG does not retain voxel size, scale, channel names, timestamps, objective details, stage coordinates, or Z-spacing. Add a scale bar only to a presentation copy, and record the calibration and display settings separately.

Whole-slide scans and stitched mosaics can be too large for common PNG viewers or require substantial memory during export. Export a region of interest, a downsampled overview, or separate tiles instead. Use OME-TIFF or another microscopy-aware format when an exchange file must preserve multidimensional image data and metadata.