Idk if this is possible currently, but you could try saving something like a tag using the picture name or data like what minecraft's NBT does, so custom paintings load across saves.
Another thing you could try doing, is what suit saver does, and just have a text file with a list of the png file names that match to the amount of paintings saved on the ship.
For example of the text idea, you have 5 paintings on the ship, one default1.png, two default2.png, one default5.png, and one default7.png.
Idk if this is possible currently, but you could try saving something like a tag using the picture name or data like what minecraft's NBT does, so custom paintings load across saves.
Another thing you could try doing, is what suit saver does, and just have a text file with a list of the png file names that match to the amount of paintings saved on the ship.
For example of the text idea, you have 5 paintings on the ship, one default1.png, two default2.png, one default5.png, and one default7.png.
The text file could appear like so:
Obviously clearing it when paintings are sold/lost, or you're ejected.