I wrote myself a program for c #, its purpose is quite simple: take a lot of cut sprites and merge into a grid.
Many store their sprites in the form of frames cut in separate images. The same result is obtained if we take some animation in the gif format and using Photoshop to save each layer as a separate frame.
It is possible to arrange such beauty manually, of course, but it is difficult. Because laziness is my middle name, I chose a different path. I run the program, I click "Select Images", selecting all the files that I need to connect, I specify the number of lines to divide the sprite sheet (rows, not columns!) I click on "Create Sprite Sheet", choosing where and in what format to save the finished sheet. The program works with png, bmp and gif formats.
Voila, the sprite sheet is ready!


