Inventory icon
Keep the silhouette readable at a tiny size. Strong edges and clean contrast matter more than tiny decoration.
Paint item and block textures in the browser, switch between 16x16, 32x32, 64x64, and 128x128, build inventory icons or tiling block faces, then send the exported PNGs into the resource-pack generator to turn them into a pack.
This canvas is intentionally simple: one PNG, one resolution, no hidden rescaling surprises. If it looks crisp here, it will stay crisp in the exported file.
Keep the silhouette readable at a tiny size. Strong edges and clean contrast matter more than tiny decoration.
Check the edges, the center contrast, and whether the face can tile without ugly seams when repeated in the world.
When the PNG is done, move it into the resource-pack generator and let that tool build the correct folder structure for you.