Adding Tile sets.

[PsychoJack]

I made a tile set for an appetizer for Atom. I made six versions, fit them all in a 96x144 grid, increase the Outside_A2.png
file by 144 height and place the tile set to the bottom-left corner. yet when I went to the tile sets in the database and choose the png for the A2(Ground) section, It doesn't show up, even when I made a new tile set.

Is it because the image have to match to replace size of the tile sets, because I don't want to replace the original sets, or is there something else I can do.

This is the tile set btw.

 

[Andar]

There are six different tilesheet formats, and each format can ONLY fit into the slot it was formatted for - A1 to A5, and the sixth format for B-E slots.

The format is not only the size of the tilesheet, but also which tiles are placed into which position - there are different autotiles going from 96x96 pixels up to 288x144 pixel (for a 3-frame animated autotile).

Additionally, what you linked above is probably not a correctly formatted autotile because an autotile is more than just a set of 96x144 pixels - it is a combination of four by six quartertiles of 24x24 pixel each, and you need to know how the engine creates the 48x48 grid from those quartertiles to be able to make a correct autotile.
I suggest you search the official blog for a tutorial named "anatomy of an autotile" to learn how to construct a correct autotile.

EDIT:
And before I forget: MV can only use full tilesheets. If you don't have enough tiles to fill the sheet, then fill the rest with transparent pixels but never use a tilesheet smaller than the norm. It will not work.