I have problems with the picture

Version

Godot Version 3.5.3

Question

when I try to make a level using tilemap, the pictures I made are stretched even though I set them to 16x16 everywhere

Are the tiles as big as the pictures?

When you bring your picture in to add it as a tile or tiles, the importer makes a guess at the dimensions of the tile. You might want to check that it’s getting that right.