Is it possible to create a Tiled map without having to create an external .tsx file?

[bjorn (Thorbjørn Lindeijer)]

Yes, see this answer:

Are embedded tilesets still supported?

Even though I’d really like to deprecate and eventually remove them, currently Tiled still supports embedded tilesets. Many people still use them and there are probably people who prefer this approach, especially if they don’t use any of the meta-information you may associate with a tileset or its tiles anyway. People can still embed tilesets in two ways: Check the “Embed in map” box when creating a new tileset when the current file is a map. Pressing the “Embed Tileset” button below the Tile…