ICO to SUN Converter

Free ICO to SUN converter — works right in your browser

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Icon Liberation

ICO files lock images into icon contexts — converting to SUN frees the visual content for use in presentations, websites, and print materials.

Data Safety First

Convertio deletes your ICO uploads instantly after processing and removes SUN output within 24 hours — no files linger on servers.

Batch Support

Queue multiple ICO files and convert them all to SUN at once — saving time when you have many files to process in a single session.

How to convert ICO to SUN

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose sun or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your sun file right afterwards

About formats

ICO is the icon file format for Microsoft Windows), introduced with Windows 1.0 in 1985 and serving as the standard container for application icons, file type icons, and shortcut icons throughout the Windows ecosystem. An ICO file bundles multiple image variants within a single container — each at different sizes (16x16, 32x32, 48x48, 256x256, and others) and color depths (4-bit, 8-bit, 24-bit, 32-bit with alpha) — allowing Windows to select the most appropriate image for each display context, from tiny taskbar buttons to large desktop icons. The container structure consists of an ICONDIR header, an array of ICONDIRENTRY records describing each variant, and the image data itself. Since Windows Vista, ICO files support embedded PNG-compressed images for the larger sizes (typically 256x256), dramatically reducing file size while maintaining quality with full alpha transparency. One advantage is automatic size adaptation — Windows pulls the optimal resolution from the ICO container for each context (Explorer list view, desktop tile, Alt-Tab preview), ensuring crisp display without the application managing separate image files. The format's operating system-level integration is another core strength: ICO files serve as the identity mechanism for executables, file associations, and shortcuts across all Windows versions, and web browsers use favicon.ico for website identity in tabs and bookmarks. ICO creation and editing is supported by image editors like GIMP, Inkscape, and dedicated icon tools, and the format remains essential for Windows application development.
Developer: Microsoft
Initial release: 1985
SUN is a raster image format associated with Sun Microsystems workstations, encompassing both the Sun Raster format (.ras) and the Sun Icon format used for window system icons and cursors on SunOS and Solaris systems. Sun Raster files, identifiable by their 0x59a66a95 magic number, store bitmap images in 1-bit monochrome, 8-bit indexed color, 24-bit BGR, or 32-bit XBGR modes, with optional run-length encoding compression and a 32-byte header. The Sun Icon subset is a simpler text-based format used for small monochrome bitmaps — window icons, cursor images, and toolbar graphics — stored as C-language data arrays that could be directly compiled into X Window and SunView applications. These icon files begin with a comment block specifying width, height, and optionally hot spot coordinates (for cursor images), followed by hexadecimal pixel values in a format readable by both the C compiler and the iconedit tool. Sun workstations running SunOS and later Solaris were foundational platforms for Unix computing, networking, and the early internet, and the SUN image formats were integral to their graphical environments. One advantage is the format's dual text/binary nature: Sun Icons are valid C source code that can be #included directly into applications, a practical approach to resource embedding that predates modern asset management systems. The Sun Raster variant's simplicity provides another strength — the 32-byte header and straightforward encoding make it one of the easiest binary image formats to parse. SUN format files are supported by ImageMagick, GIMP, XnView, and Unix image viewing tools.
Developer: Sun Microsystems
Initial release: 1982

Frequently Asked Questions

Why convert ICO to SUN?

Sun icon/raster makes your image native to Solaris systems — required when building UI elements for Sun workstation desktop environments.

What programs open SUN files?

Common options include GIMP, ImageMagick, Sun/Solaris applications. The format has good support across major operating systems.

Is the conversion process fast?

ICO to SUN conversion usually finishes in a few seconds. Larger files may take slightly longer, but the cloud-based processing keeps things efficient.

Can I convert ICO to SUN for free?

Yes — Convertio offers free ICO to SUN conversion. For professional volumes and larger files, premium plans provide expanded limits and priority processing.

Can I convert multiple ICO files at once?

Yes — Convertio supports batch uploads. Queue several ICO files and convert them all to SUN format in a single session without repeating steps.

Does this work on mobile devices?

Yes — the ICO to SUN converter works in any mobile browser on iOS and Android. No app installation is needed — just open convertio.tools and upload your file.