SK1 file (SK1) stores data in the SK1 format. Windows Icon (ICO) bundles multiple raster images at different resolutions (16x16 through 256x256) into a single file for use as application icons. This renders each page as a raster image, making the content viewable without a document reader. Each page is rendered at the specified DPI and saved as a separate image; text in the output is no longer selectable. The result is a standard ICO file readable by any compatible application. 1converter handles SK1-to-ICO conversion server-side: files are uploaded over HTTPS, processed on isolated cloud infrastructure, and the converted output is available for download for 24 hours before automatic deletion. No account is required for standard conversions.