seamless join PNGs one above the other

Question

How can I use ImageMagick (probably the montage command) to join png images into a new png, where each of the input pngs becomes a part of the final one? All vertically arranged?

Like so:

2 pngs of roughly equal width (±2px) and different heights joined on top of one another seamlessly.

I don't really mind so much what happens to excess/smaller widths.

Answer 1

this one:

convert -append img1.png img2.png out.png

e.g. from

will get

And the:

convert +append img1.png img2.png out2.png

will produce

Answer 2

convert 1.png 2.png -append result.png

• To align left edges, add -gravity West.
• To align right edges, add -gravity East.
• To align centres, add -gravity center.

To add a transparent spacer between:

convert -background none 1.png -size 10x10 xc:none 2.png -append result.png

Oh, you've gone horizontal! Change -append to +append.