CONVERT
ICO → MIFF
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Fast, secure ICO to MIFF conversion. No registration required.
ICO is the Windows icon container with multiple resolutions packed into one file. Reaching a MIFF from there is one hop. A ICO → MIFF 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. Worth knowing: ICO is the Windows icon container with multiple resolutions packed into one file. Meanwhile MIFF 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.
ImageMagick MIFF
Target formatMIFF (Magick Image File Format) is the native format of ImageMagick, supporting all of its internal features including multiple image layers, color profiles, and arbitrary metadata. It serves as a lossless interchange format within ImageMagick processing chains.
Why convert ICO to MIFF
The real reason to move from ICO to MIFF 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 MIFF solves those edge cases at the cost of a short conversion step.
HOW TO CONVERT
ICO → MIFF
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 MIFF
The conversion decodes the ICO, resolves the colour space to sRGB and writes the MIFF container around the pixel data.
Save the MIFF
The download is streamed back over HTTPS. If you uploaded multiple files, a ZIP with all MIFF outputs is produced instead.
Common Use Cases
Document embeds
Word, Google Docs and Pages embed MIFF with correct aspect ratio; ICO may appear as a broken image icon.
Printer-friendly export
Consumer and office printers drive MIFF through their print spoolers with no additional drivers.
Presentation slides
PowerPoint and Keynote treat MIFF 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 MIFF as the only accepted image format.
ICO vs MIFF — 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).
MIFF Strengths
- Preserves ImageMagick's full fidelity.
- Arbitrary bit depth + color profile.
- Streaming pipeline intermediate.
Limitations
- ImageMagick-only.
- Not a delivery format.
- Large files.
ICO vs MIFF — Technical specifications
Side-by-side comparison of the technical details.
ICO
- MIME type
- image/vnd.microsoft.icon
- 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+)
MIFF
- MIME type
- image/x-miff
- Extension
- .miff
- Native tool
- ImageMagick
- Bit depths
- Any (ImageMagick-supported)
| Specification | ICO | MIFF |
|---|---|---|
| MIME type | image/vnd.microsoft.icon | image/x-miff |
| 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 | — | .miff |
| Native tool | — | ImageMagick |
| Bit depths | — | Any (ImageMagick-supported) |
ICO vs MIFF — 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
MIFF
- 1920×1080 8-bit MIFF ~6 MB
- 1920×1080 32-bit float ~25 MB
Quality & Compatibility
ICO-to-MIFF 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 MIFF copy.
Tips for Best Results
- Large ICO files may look identical to small MIFF files for photographic content; pick quality based on end use, not headline megapixels.
- For print, export MIFF 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
It depends on the codecs involved. If both ICO and MIFF are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If MIFF 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 MIFF is lossless. ICO tuned for efficient web delivery will usually produce smaller files than MIFF'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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Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.