ICO is a format (full name - Icon File) of bitmap images and refers to system files. Developed by Microsoft and designed to store icons in its operating system. ICO files, as a rule, store icon images - modest in size, with a small resolution (from 16x16 to 64x64 pixels), with different color depths (from 16 colors). In the graphical interface of various operating systems, ICO format files are used to display files, programs and folders (primarily in Windows) or as an icon for a specific website.
TIFF is a format that allows you to store raster graphics with tags. It was developed by Aldus Corporation in conjunction with Microsoft so that it can be used with PostScript. Aldus Corporation owns specifications. Subsequently, this company merged with Adobe Systems. It is she who now owns the copyright to these specifications. Typically, TIFF files (Tagged Image File Format) are with the extension .tiff or .tif. Aldus was specifically engaged in the development of the format in order to achieve the preservation of scanned images. The popularity of TIFF can be explained by the fact that it is preferred in order to store images that have a large color depth. The format is used to send faxes, scan, recognize texts. It is widely supported in the printing industry. TIFF was chosen as the main graphic format of the NeXTSTEP operating system. Then from this system TIFF support migrated to Mac OS X. At first, the format supported lossless compression. Then it was supplemented in order to support lossy compression in JPEG format. We emphasize that the maximum weight of a document, if stored in this form, is no more than 4 GB. To open a TIFF file larger than 2 GB, you must run Photoshop CS.