ICO (Icon file) is a ICO format commonly used for favicons, desktop app icons, multi-size icon bundles. This guide covers compatibility, compression, transparency, and conversion choices.
| Feature | Support |
|---|---|
| Transparency | alpha_or_mask |
| Animation | No |
| Primary uses | favicons, Windows application icons, multi-size icons |
Extension
.ico
Compression
depends
Browser support
favicon_context
Inventor
Microsoft
Inventor organization
Microsoft
Origin year
1985
Multiple icon sizes in one file
Windows integration
Narrow use case
Not for normal photos
ICO is a container format commonly associated with favicons, Windows application icons, multi-size icons. It should be explained with its compression, transparency, metadata, browser support, and conversion tradeoffs rather than as a generic upload option.
ICO origin and standardization should be reviewed against the source references before publication.
Choose conversion targets based on ICO compression, transparency, animation, metadata, and compatibility requirements.
Quality behavior depends on ICO compression: depends.
Uploaded files may contain metadata. Preserve color profiles intentionally and strip GPS/Exif when privacy matters.
Windows and browser favicon workflows.
format slug
ico
inventor
Microsoft
strengths
Multiple icon sizes in one file, Windows integration
use cases
favicons, Windows application icons, multi-size icons
weaknesses
Narrow use case, Not for normal photos
color depth
Multiple embedded icon sizes and depths.
compression
depends
origin year
1985
standard owner
Microsoft ecosystem
browser support
favicon_context
metadata support
icon directory entries
software support
Windows and browser favicon workflows.
animation support
none
compression method
Container for BMP-like icon bitmaps and modern PNG icon images.
best source formats
png, svg
best target formats
png
transparency support
alpha_or_mask
inventor organization
Microsoft
ICO transparency support is: alpha_or_mask. Choose a target format with alpha support when transparent backgrounds matter.
Convert ICO when another format better matches compatibility, file size, transparency, metadata, or editing needs.
ICO is best suited to favicons, Windows application icons, multi-size icons.
ICO compression behavior is: depends.
Strip GPS and personal metadata for public sharing. Preserve ICC/color profiles when appearance matters.
Browser support is: favicon_context.
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