How to Change Your Discord Status Image and Text in Simple Discord Rich Presence
Editing the config file
Open your Minecraft instance folder and find the config directory. Inside it, look for the Simple Discord Rich Presence config file (it is a plain text config, not a binary one). Open it with any text editor. You will see a small set of options: the Discord application ID, and toggles for the different states the mod reports. Change the application ID to your own Discord application if you want custom art, then save the file.
Applying your changes
The mod reads the config when the game starts, so a running game will not pick up edits. Fully close Minecraft, then launch it again. Join a world and check your Discord profile — the status should now reflect your edited settings. If nothing changed, confirm you edited the file in the correct instance folder (mod loaders keep separate config folders per instance) and that you did not leave a syntax error such as a missing quote around the application ID.
Using your own art
If you supplied your own application ID, the images come from that application's art assets. Upload the images you want to that application, name the assets, and reference those asset names in the config where the mod expects an image key. The dimension icons the mod ships with only appear when you keep the default application.