Flash is completely correct and right. 1.23 is much better for your tilesets, expectelly because most of the older players preffer to play it over TSF. That'll ruin the chance of seeing your cool conversions being used.

If you don't have 1.23, send your tilesets in .bmp format to me (Moonblaze_@hotmail.com), and I'll convert them to 1.23 for you, so you can reupload them.