ICO vs ORF
A detailed comparison of ICO Icon and Olympus RAW ORF — file size, quality, compatibility, and which format to choose for your workflow.
ICO Icon
Raster & Vector ImagesICO 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.
About ICO filesStrengths Comparison
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.
ORF Strengths
- Compact files relative to sensor size (Four Thirds is smaller than APS-C).
- Computational photography features (Live Composite, Pro Capture) baked into format.
- Stable across 20+ years of Olympus/OM SYSTEM bodies.
- In-body stabilization means ORF handheld shots rival tripod work.
Limitations
ICO 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).
- Editing requires specialized tools — most image editors treat it as a curiosity.
ORF Limitations
- Smaller sensor means less dynamic range than full-frame raws.
- Lossy compressed ORF is the default — hidden quality loss.
- Market share is small; fewer tutorials and fewer Lightroom profiles.
- Proprietary with no official spec.
Technical Specifications
| Specification | ICO | ORF |
|---|---|---|
| MIME type | image/vnd.microsoft.icon | image/x-olympus-orf |
| 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+) | — |
| Extension | — | .orf |
| Container | — | TIFF/EP with Olympus MakerNote |
| Sensor format | — | Four Thirds / Micro Four Thirds |
| Bit depth | — | 12 or 14-bit |
Typical File Sizes
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
ORF
- 20 MP ORF (OM-1, E-M1 III) 18-25 MB
- 50 MP Hand-Held High Res composite 60-80 MB
- 80 MP Tripod High Res ORF 100-140 MB
Ready to convert?
Convert between ICO and ORF online, free, and without installing anything. Encrypted upload, automatic deletion after 2 hours.
Frequently Asked Questions
ICO (Icon) is Microsoft's 1985 multi-resolution icon format, originally shipped with Windows 1.0. A single .ico file holds multiple sizes (16×16, 32×32, 48×48, 256×256) so the OS can pick the best one for the current display context. Since 1999, every website uses a favicon.ico to show its icon in browser tabs.
On Windows, ICO files open natively in File Explorer and Photos. On macOS, Preview handles basic display. For editing, use GIMP (free), Photoshop with a plugin, or dedicated icon editors like IcoFX.
Use the PNG-to-ICO converter on KaijuConverter — upload a PNG (ideally square, at least 256×256) and download a multi-resolution ICO with all standard favicon sizes embedded.
A complete favicon pack includes 16×16, 32×32, 48×48, and 256×256 px variants all in one ICO file. The total file size is typically 5-15 KB. Browsers automatically pick the right size for tabs, bookmarks, and desktop shortcuts.
ICO for /favicon.ico (every browser requests this URL automatically). PNG for everywhere else — social media profile images, in-page icons, app logos. Modern favicon best practice includes both an .ico at the root and multiple .png sizes referenced via <link> tags in HTML.
Yes. Every browser still requests /favicon.ico on every domain as its first icon fallback. Modern sites typically provide both favicon.ico and higher-quality SVG or PNG icons via <link rel="icon"> tags — browsers pick the best match.