roundand

@echo off
SET st3Path=C:\Program Files\Sublime Text 3\sublime_text.exe
 
rem add it for all file types
@reg add "HKEY_CLASSES_ROOT\*\shell\Open with Sublime Text 3"         /t REG_SZ /v "" /d "Open with Sublime Text 3"   /f
@reg add "HKEY_CLASSES_ROOT\*\shell\Open with Sublime Text 3"         /t REG_EXPAND_SZ /v "Icon" /d "%st3Path%,0" /f
@reg add "HKEY_CLASSES_ROOT\*\shell\Open with Sublime Text 3\command" /t REG_SZ /v "" /d "%st3Path% \"%%1\"" /f
 
rem add it for folders
@reg add "HKEY_CLASSES_ROOT\Folder\shell\Open with Sublime Text 3"         /t REG_SZ /v "" /d "Open with Sublime Text 3"   /f

darsain

To make this work in CSS:

background: url('images.svg#chart');

or img:

<img src="images.svg#chart">