CONVERT
ICO → SGI
Fast, secure ICO to SGI conversion. No registration required.
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ICO is the Windows icon container with multiple resolutions packed into one file. Reaching a SGI from there is one hop. A ICO → SGI operation is one of the simplest image jobs there is: same pixel grid, different wrapper. What genuinely changes is how lossy the codec is, whether alpha survives, and how large the final file ends up. KaijuConverter picks safe defaults for each of those and lets you override them under Advanced. In practice ICO is the Windows icon container with multiple resolutions packed into one file. On the other end, SGI is a raster image format with its own balance of compression, colour depth, and software support.
ICO Icon
Source formatICO is the icon file format used for favicons and Windows application icons. A single ICO file can contain multiple image sizes and color depths for different display contexts.
SGI Image
Target formatSGI (Silicon Graphics Image) is a raster image format developed by Silicon Graphics for use on their IRIX workstations. It supports both uncompressed and RLE-compressed storage with up to 4 channels including alpha.
Why convert ICO to SGI
The real reason to move from ICO to SGI is almost never picture quality — both raster formats store essentially the same pixels. It is about the tools downstream: which editors open the file natively, which CMSes upload it without transcoding, which social platforms accept it. Picking SGI solves those edge cases at the cost of a short conversion step.
HOW TO CONVERT
ICO → SGI
Provide the ICO
Click or drag to upload. We accept a single ICO file per job, with an optional queue of additional images for batch mode.
Encode to SGI
The conversion decodes the ICO, resolves the colour space to sRGB and writes the SGI container around the pixel data.
Save the SGI
The download is streamed back over HTTPS. If you uploaded multiple files, a ZIP with all SGI outputs is produced instead.
Common Use Cases
Document embeds
Word, Google Docs and Pages embed SGI with correct aspect ratio; ICO may appear as a broken image icon.
Printer-friendly export
Consumer and office printers drive SGI through their print spoolers with no additional drivers.
Presentation slides
PowerPoint and Keynote treat SGI as a first-class citizen; ICO may need manual re-insertion per slide.
Online form uploads
Identity verification, job applications and legal forms often list SGI as the only accepted image format.
ICO vs SGI — Strengths and limitations
What each format does best, and where it falls short.
ICO Strengths
- Multi-resolution: one file, many sizes, OS picks the right one.
- Universal favicon support in every browser since IE5.
- Supports transparency (1-bit since 1985, full alpha since XP).
- Tiny file size — an entire favicon pack typically fits in under 15 KB.
- No licensing or patent concerns — fully in the public domain spec-wise.
Limitations
- Cannot compress continuous-tone images efficiently — use PNG or WebP for photos.
- Format is essentially frozen in 1999 — no HDR, no wide gamut, no modern features.
- Maximum image dimension is 256×256 px (inside an ICO container).
SGI Strengths
- Historic VFX pipeline format.
- 16-bit channel support.
- RLE compression.
- ImageMagick compatibility.
Limitations
- Legacy — SGI Inc. is gone.
- Superseded by OpenEXR/DPX in film.
- Niche tooling.
ICO vs SGI — Technical specifications
Side-by-side comparison of the technical details.
| Specification | ICO | SGI |
|---|---|---|
| MIME type | image/vnd.microsoft.icon | image/x-sgi |
| Max resolutions per file | 65 535 images | — |
| Max single image size | 256×256 px | — |
| Color depths | 1, 4, 8, 24, 32 bits per pixel | — |
| Compression | Uncompressed bitmap or embedded PNG (Vista+) | None or RLE |
| Extensions | — | .sgi, .rgb, .rgba |
| Bit depth | — | 8 or 16 bits per channel |
ICO vs SGI — Typical file sizes
Approximate file sizes for common scenarios.
ICO
- Classic favicon (16×16 only) < 2 KB
- Multi-size favicon pack (16/32/48/256) 5-15 KB
- Full Windows app icon set 20-100 KB
SGI
- 1080p 8-bit SGI frame 4-8 MB
- 4K 16-bit SGI 50-100 MB
Quality & Compatibility
ICO-to-SGI conversion does not change the visible content. Quality is capped by the ICO decode; re-encoding a lossy source at high quality cannot recover detail that was already discarded. For archival masters, keep the original ICO alongside the SGI copy.
Tips for Best Results
- Large ICO files may look identical to small SGI files for photographic content; pick quality based on end use, not headline megapixels.
- For print, export SGI at 300 DPI minimum and check that the colour profile embedded matches the print shop specification.
- Batch-convert related ICO images in one pass so they share identical encoder settings and look consistent side-by-side.
Frequently Asked Questions
Frequently Asked Questions
It depends on the codecs involved. If both ICO and SGI are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If SGI is lossless (PNG, TIFF, BMP) the output keeps every pixel of the decoded ICO exactly, but cannot recover detail that ICO had already compressed away.
Often yes, especially when SGI is lossless. ICO tuned for efficient web delivery will usually produce smaller files than SGI's default settings. If file size matters, drop the quality in Advanced or pick a more compressed target format instead.
KaijuConverter uploads over HTTPS, processes the image in an isolated container and deletes both the source and the output within two hours. No account is required, file contents are never logged, and we do not use uploads to train any model. For confidential material, the paid plan includes a data-processing agreement.
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Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.