Batch assembling images in different folders

(X-Post as I've been told this requires scripting)

Hello,

I have two folders with files named with numbers (from 0 to 400 or 500 something). The filenames are the same in each of the two folders. How can I automate the "assembly" of an image using the files with the same name?

Both 0.png and 0.png are 80x80, and I need to assemble them into one 80x160 file.

I know a bit about Batch but I don't know how to make it open a file with its same name from another folder or how to place it (I know how to increase canvas size).

To go over the desired outcome again:

- I have many files named after numbers in different folders.

- I need to open all the files (all 80x80) in one folder, and open the same file with the same filename (so 0.png opens 0.png in the other folder, 1.png opens 1.png...)

- Increase canvas size (this I can do with an Action, but I do not know how to insert it into a script either)

- Place the second file at a particular location (after the first 80x80 file, after the canvas has been enlarged to 80x160)

- Save to a third folder, with the same filename

Any help is welcome. Thank you.

I am currently taking a look at these threads:

Re: Batch sequence from 2 folders Re: (cross post) Batch of two folders in...

I think I can use the first thread to merge the files. Right now Im batch enlarging canvas size, so all are 80x160 (increasing size from opposite directions), so when they merge, both images are where they need to be. I will report as soon as I can.