This is arguably the most important concept to master. A "Metatile" (or Block) tells the game to arrange four 8x8 tiles to make a 16x16 image.
The GBA hardware limits tilesets to 16-color palettes (with the first color reserved for transparency). Managing these palettes is the most difficult part of tile insertion, as new graphics must be "recolored" to fit existing palettes or risk appearing with distorted colors. Mapping and Customization For creators using tools like RPG Maker XP Pokémon Essentials pokemon fire red tilesets
: Sites like DeviantArt host "rips" or complete outdoor tileset collections that compile all default game graphics into usable sheets. This is arguably the most important concept to master
If you are looking for ready-made visual features, these patches provide comprehensive replacements for the original FireRed graphics: Managing these palettes is the most difficult part
: Collections of these blocks. Every map in the game uses exactly two tilesets :