JPG to RAS Converter
Convert JPG to RAS in your browser. JPG files usually come from cameras, phones, scanners and almost every app that saves photos; RAS is the better fit for legacy Sun and Unix software. You get a 24-bit run-length encoded Sun Raster image. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
JPG expected · other image formats also work
How to use JPG to RAS
- 1
Add your JPG files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the RAS is written losslessly. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .ras files one at a time or together as a ZIP.
Why use Aback Images for jpg to ras
Where the RAS goes next
RAS opens in ImageMagick, GIMP, XnView, IrfanView and Netpbm.
RAS next to JPG
The RAS keeps the decoded pixels without lossy compression, so expect it to be larger than the JPG.
No new artefacts
JPG is already lossy, since it stores lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution; the RAS keeps the decoded pixels losslessly, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
JPG vs RAS
What changes from JPG to RAS
Encoding: the JPG uses lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution; RAS uses none or a byte-oriented run-length encoding (RT_BYTE_ENCODED), and the download is a 24-bit run-length encoded Sun Raster image.
Bit depth: 8 bits per channel in the JPG; RAS allows 1, 8, 24 or 32 bits per pixel, and the RAS written here has 24 bits per pixel.
Colour: YCbCr shown as RGB, greyscale, or CMYK from print software in the JPG; RAS supports monochrome, a colour map, or RGB stored as BGR, written here as 8-bit sRGB.
Metadata: the JPG can carry EXIF (camera, date, GPS), XMP, IPTC and an ICC profile in APP segments; RAS can carry only a 32-byte header with size, depth, type and colour map length, but nothing is copied across.
About JPG
JPEG is the universal photo format. It compresses by discarding fine detail the eye is least sensitive to, which makes photos small but blurs sharp edges and text if pushed too far.
A JPEG starts with the bytes FF D8 and is a run of marker segments: APP1 carries EXIF and often a thumbnail, APP2 an ICC profile, DQT the quantization tables that decide the quality, and SOS the compressed scan, which ends at FF D9.
JPG files usually come from cameras, phones, scanners and almost every app that saves photos.
About RAS
Sun Raster is the bitmap format of Sun Microsystems' SunOS and Solaris workstations. It stores 1, 8, 24 or 32-bit pixels, optionally with a colour map and simple run-length compression.
A Sun Raster file starts with the magic number 59 A6 6A 95 and a 32-byte header (width, height, depth, data length, type, colour map type and length), then the colour map and the rows, each padded to an even number of bytes.
When converting JPG to RAS makes sense
RAS is the better choice for legacy Sun and Unix software, while JPG suits photographs that need to open anywhere.
RAS strengths: Simple and well documented; Read by ImageMagick, GIMP and many viewers. Drawbacks to weigh: Obsolete outside old Unix systems; No transparency in practice; Weak compression.
Limitations
- JPEG artefacts already in the file, such as blocking near edges and smeared colour, are kept as pixels: a lossless target preserves them faithfully rather than removing them.
- Sun Raster has no alpha channel, so transparency is flattened onto the background colour.
- Modern viewers such as IrfanView, XnView and GIMP still open it.
More conversions
Related tools
Convert RAS to JPG in your browser, ready for photographs that need to open anywhere. Batch, private, no uploads.
Convert JPG to PNG in your browser, ready for screenshots, logos, graphics and anything that needs transparency. Batch, private, no uploads.
Convert JPG to WebP in your browser, ready for images on websites and in apps. Batch, private, no uploads.
Convert JPG to AVIF in your browser, ready for maximum compression on modern websites. Batch, private, no uploads.
Convert JPG to HEIC in your browser, a HEIF file with JPEG compression inside. Batch, private, no uploads.
Convert JPG to GIF in your browser, ready for short animations and reactions that must play everywhere. Batch, private, no uploads.
Convert JPG to PDF in your browser, one PDF page per image. Batch, private, no uploads.
Convert JPG to SVG in your browser, traced into real vector paths. Batch, private, no uploads.
Frequently asked questions
Does converting JPG to RAS lose quality?
RAS is written losslessly, so the pixels are stored exactly as decoded. Artefacts already in the JPG stay, but nothing new is lost.
Which apps open RAS files?
ImageMagick, GIMP, XnView, IrfanView and Netpbm. It does not open in web browsers.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.