These are graphics for SMAS:SMB3 Ice Blocks and Frozen Blocks.
It contains both the original SMAS:SMB3 Ice Blocks, as well as others drawn based on their style.
It also contains some frozen items/blocks meant to be used with Ersanio's "Icy/Frozen Blocks Pack".
Check the included ReadMe for info on this.
The submission contains one ExGFX file, one palette file (and palmask), one Map16 file, one sample level and the readme.
The ExGFX file uses the BG2 slot, and the palette uses the palette row 6 (with the ice blocks using the right side of the palette), so it doesn't overwrite anything from the original game.
Credits aren't mandatory, but would be appreciated! =D