I have no idea how many people are hatred of unaligned images in a row but sure I am one of them. Please use this application when you align images in a row.
Tunacan, a simple image concatenator originally just designed for my use, is now available on the Mac App Store for free with brand new experimental user interface. Drag images from Finder, adjust spacing between images, “Export” to write them into a combined PNG file. Images are resized automatically, so that they can fit into one row. Enjoy animation and sound feedbacks on your every single action. They have no effect on exported image though.