Defining the file order for ImageMagick convert

You just give the order of your PNG files as they should appear in the animation. Use:

foo0.png foo5.png foo10.png foo15.png foo20.png foo25.png

instead of

foo*.png

After all, it's only 6 different file names which should be easy enough to type:

convert                                                      \
  -delay 10                                                  \
   foo0.png foo5.png foo10.png foo15.png foo20.png foo25.png \
  -loop 0                                                    \
   animated.gif

Simple and easy, list your images and sort them:

convert -delay 10 -loop 0 $(ls -1 *.png | sort -V) animated.gif

If you have more input images than are convenient enough to type (say, foo0..foo100.png), you could do this (on Linux, Unix and Mac OS X):

convert                                                  \
  -delay 10                                              \
   $(for i in $(seq 0 5 100); do echo foo${i}.png; done) \
  -loop 0                                                \
   animated.gif