It’s still possible to use the Photoshop plugin by Telegraphics to create favicons and .ico images. Here’s how.
Creating a favicon for your website with the file extension .ico is still possible in Photoshop 2020 (also described as Photoshop CC 2020 and Photoshop 2020 CC). Make sure Photoshop is not running before beginning this installation.
1. Go to the website for Telegraphics:
http://telegraphics.com.au/sw/product/ICOFormat#icoformat
2. For macOS 10.15.1 (macOS Catalina), click on “Mac CS5/CS6.” The file is currently called ICOFormat-2.1b1-CS5.dmg. Download it. If the download is blocked, you may need to go to System Preferences > Security & Privacy and grant access to download.
3. Double click on ICOFormat-2.1b1-CS5.dmg once downloaded. It will become ICOFormat.plugin. Make a note of where that plugin is located. If you downloaded the .dmg to your Downloads folder, the plugin will be there also.
4. Go to Macintosh HD > Applications > Adobe Photoshop 2020 > Plugins.
5. Create a folder called “File Formats” if there isn’t one already there.
6. Move ICOFormat.plugin into the “File Formats” file.
7. Open Photoshop 2020. Create a new image that is 256×256 and 72dpi. Go to File > Save As and verify that the ICO (Windows Icon) file extension is an option.
NOTE: Your Photoshop image must be smaller than 256px by 256px in order for the .ICO file save option to be present. If it’s bigger than that, it won’t show up in the dropdown of file format options.