Using the tools provided with ImageMagick
We can easily join, i.e. "montage" images into one large image with the following command
montage -geometry 500 image1 image2 [...] output
See the project page for many parameters of the geometry option. CAUTION: the output argument is non-optional, having just two images on argument list ends up replacing image2 without warning. In the example above all images will be scaled to a width of 500
pixels before they are joined. Adapt this value for your image sizes. In case you need to have a fixed height choose x500
instead. The other dimension will be scaled to preserve the aspect ratio.
Inspired by this post saying that ImageMagick has command line tool named convert
to merge images. To join images horizontally (in alphabetical order):
convert +append *.png out.png
To stack images vertically:
convert -append *.png out.png
That should be run in a terminal into the folder containing png files to join them all.
A gui for that would be:
a file manager context menu to join selected images.
An easy way when it comes to that is Thunar's custom actions:
To join selected images vertically (into one png
file, in alphabetical order, no matter their extension) add this custom action:
convert -append %F joined-vertical.png
To join horizontally:
convert +append %F joined-horizontal.png
For a more sophisticated way to assemble images you may want to search for panorama photo stitcher software such as hugin
or the Pandora plugin for Gimp.