How were these tiles made?
They probably covered the tile in white glaze and then used a paint brush or sponge stamps to apply the blue glaze on top of the dried (but not fired) white glaze.
Unfortunately the only source I could find is a German documentary without any subtitles, but starting at 28:10 it clearly shows a potter applying different patterns by sponging pigmented engobe onto unfired clay items.
She explains that she made all of her sponge stamps herself by drawing a motif onto a fine sponge and either cutting the excess away with nail scissors or burning fine lines into the sponge with a soldering iron.
To apply the pattern, the sponge has to be damp. The clay item is covered with a first coat of engobe. After the first coat dried, the sponge stamp is dipped into a very shallow pool of engobe and then stippled onto the clay item.
You won't get perfectly crisp lines with this method, but especially the bottommost picture you posted looks like it was sponged. You can even see a very slight sponge pattern in there. All of the other tiles have very smooth lines and are most likely hand painted, but I can imagine that you can stamp a guiding pattern onto the tile and then follow that pattern with a paint brush.