Easy way to paste multiple images together?

[Ofnuts]

Two ways:

Semi-manual

• load all images as layers if not already done (File>Open as layers, and you can select multiple images to load everything in one go)
  
• Put them roughly where you want them (they just need to be in the right order)
  
• Use my arrange-layers script (Space option)
  

Automatic, if the files names are sorted in the same order as the cards positions:

      * With my ofn-tiles plugin, use File>Open tiles, give it a directory and a pattern, set Columns to 1 and Rows to the number of cards.

arrange-layers is described here. (ofn-tiles comes with its own documentation)

Both are downloadable here.