The default is 16x16, but you can use HD texture packs that can go much higher, 64x64, 128x128, 256x256... Etc
Chat with our AI personalities
Texture Resolution
Yes they are 100% safe although it may lag your minecraft (depending on the texture pack) if its a really high resolution one and u don't have a very good computer/laptop
For HD texture packs (over 16x16 in resolution), you have to use either MCPatcher or OptiFine in order for the textures to work and animate correctly.
100% minecraft
You can email Minecraft if you have any questions about Minecraft. That's what the Minecraft Help Email is.