Is there a way to change skill icon?

ruikkarikun

Maybe with some addon?

I saw a picture from lui extended, there was something about custom icons, but I can't find any in its settings.

Ilision

I believe what you saw/read was the custom icons that you see in the screenshot. Those icons are not interchangeable. They are added to best resemble the in-game ones, that's all.

Below you can find the actual noted from the addon page, (https://www.esoui.com/downloads/info818-LuiExtended.html)

"Custom icons added for Potions, Poisons, Food, & Mementos.
Custom icons for Champion Point Abilities, Item Sets, Weapon Abilities, and many NPC abilities (See screenshots for more)."

Hope this helps.