Metadata on tilesheet?

Hello everyone,

I’m making a platform game, and have put the frames of the character inside a tilesheet (instead of a MovieClip). The first tile is the ‘idle’ state, tiles 2, 3 and 4 are for 'walking, etc.

Because the tiles are in a tilesheet, they all have the same width and height. What is the best way to store data about the actual size of each tile? For example, tile 1 is 16x24, the rest is empty, while tile 2 is 20x23. Should I store each ‘dimension’ in an Array, or is there a better way?