PNG to FITS Converter
Processing entirely on your device — large files may take a moment.
Convert FITS frames to PNG or JPG to preview telescope data, or pack them into a ZIP for sharing. If your files are still in PNG format, this page is the shortcut: PNG is a lossless image format that preserves every pixel exactly and supports transparent backgrounds, which makes it the standard for screenshots, logos and graphics containing text or sharp edges.
iLoveConverter processes everything locally on your computer, which makes it private and fast: no upload wait, no server storage, no limits. Add as many files as you like — batch conversion is built in.
How PNG compares to FITS
| PNG | FITS | |
|---|---|---|
| Compression | Lossless (DEFLATE) | None (optionally Rice/GZIP) |
| Transparency | Full alpha (8/16-bit) | Not supported |
| Animation | Only via APNG extension | Not supported |
| Metadata | tEXt chunks, ICC profile | Rich text header (WCS) |
| Best for | Screenshots, logos, sharp graphics | Telescope frames, science data |
How to convert PNG to FITS
- 1
Select your files
Drag & drop your PNG files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to FITS". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted FITS file individually, or grab everything at once as a ZIP archive.
About the PNG format
PNG was created in 1996 as a free, open replacement for the patent-encumbered GIF, and it has been the reference lossless image format ever since. Pixels are compressed with the DEFLATE algorithm (the same one inside ZIP files), which reproduces the original image exactly — bit-for-bit — while supporting full 8-bit or 16-bit alpha transparency. Screenshots, logos, icons, charts and anything with text or sharp edges should live in PNG.
Because it never discards information, PNG files of photographs are several times larger than JPG — that is the price of perfection. Modern PNG encoders add filters per scanline that make screenshots and flat-color graphics compress surprisingly well. PNG also became the base of APNG, the animation extension that browsers play natively.
+Strengths
- ✓Truly lossless — every pixel survives exactly as it was
- ✓Full alpha transparency with smooth edges, not 1-bit masks
- ✓Open standard, unpatented, with excellent tooling everywhere
- ✓Ideal for text, line art and flat-color graphics — sharp edges stay sharp
!Limitations
- −Photographs become several times larger than JPG
- −Base format has no animation (that is the APNG extension)
- −16-bit or high-resolution PNGs can grow very heavy
About the FITS format
FITS (Flexible Image Transport System) has carried professional astronomy data since 1981: every file opens with a plain-text header that records telescope, instrument, exposure, filters and world coordinates, followed by raw pixel arrays — often 16-bit or float, sometimes data cubes.
Values can be negative or far above display range, so FITS never looks right in a photo viewer. Converting to PNG applies a simple scaling pass that reveals the nebula or galaxy in the numbers — good for previews, while science pipelines keep the original.
+Strengths
- ✓Self-documenting science headers
- ✓High bit depth (16/32-bit, float)
- ✓The standard of every observatory
!Limitations
- −Not display-ready
- −Files are large and uncompressed
Why convert PNG to FITS?
There is a concrete reason this conversion exists: Photographs become several times larger than JPG FITS sidesteps that — Self-documenting science headers If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this PNG to FITS converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Will I lose quality converting PNG to FITS?
No — FITS is a lossless format, so every pixel of the converted image matches your original PNG file. You can also adjust the quality/size balance before converting when the target format supports compression.
What happens to EXIF data and other metadata?
Conversions here re-encode the image, and re-encoding generally does not carry the original metadata over. If the EXIF data of your PNG files matters (camera model, GPS, timestamps), keep the original file as the master and treat the converted copy as the shareable version.
Can I convert several PNG files at once?
Yes — drop as many files as you like into the tool and they are converted in one batch. When more than one file comes out, everything is bundled into a ZIP for a single download.