BlueMap supports the use of minecraft resource-packs. If you want to change the appearance of your map, use high resolution textures or fancy block-models.
Important:
If you change your resource-pack setup you need to delete your previous renders! Delete the complete web/data folder! Otherwise you will get broken models with really weird textures.
To install a resource-pack you just need to put the resource-pack folder or zip in the folder resourcepacks next to your configuration files and reload BlueMap. BlueMap will scan the folder and try to load every resources it finds.
Sponge, Forge, Fabric: ./config/bluemap/resourcepacks/
Spigot/Paper: ./plugins/BlueMap/resourcepacks/
You can use more than one resource-pack. Like in minecraft, they will override each other. They are loaded in alphabetical order, so a resource-pack called zzzresources.zip will override aaaresources.zip.
This means you can reorder them by renaming them e.g. 01_some_pack.zip, 02_some_extension_pack.zip...
Make sure the resource-pack is for the correct minecraft-version. Otherwise it might not be loaded correctly.
There might be warnings in the console if you are using resource-packs that have some unexpected formatting. A warning mostly results in a single (block-)model not loaded correctly, so all the other resources from that resource-pack are still being loaded.