i have the problem that a name of a npc only allows 16 characters
Minecraft 1.13+ has no limit for armorstands names.
You can put an armorstand on top of the NPC in order to show longer texts.
And it looks like this there is no image.
That is because you have to use the PlaceholderAPI to replace stuff in places where ItemsAdder doesn't.
https://itemsadder.devs.beer/plugin-usage/placeholderapi
Or you can call the ItemsAdder method to replace the `:img_XXX:` ones: replaceFontImages
fontImageWrapper.applyPixelsOffset(-200);
Can i do it with this code?
Yes, it will work too. Get the returned value.
From the docs:
* Get a copy of the font_image String with pixel offset applied to it.
* Doesn't modify the original one.