The japng.jar can also be used as a command line tool. It requires Java 5.
Usage: java -jar japng.jar <options>
-out <file> The name of the output file (required)
-frames <file1>,<file2>,<file3>...
The names of the PNG files to use for the frames.
Instead of specifying all frame files on the command
line, <file1> can point to a plain text file containing a
list of frame specifications. Each line in the file
represents a frame specification of the form:
<framefile>; <display>; <dispose>; <blend>
Only <framefile> is required per line.
-display <millis1>[,<millis2>,<millis3>,...]
The display times for the frames in milliseconds.
Default : 1000 (1 sec.)
-dispose <dispose1>[,<dispose2>,<dispose3>,...]
The disposal operations to perform after each frame.
dispose : [none|background|previous]
Default : none
-blend <blend1>[,<blend2>,<blend3>,...]
The blending operations to perform when painting each frame
blend : [source|over]
Default : source
-play <number> The number of times to play this animation.
Default : 0 -> infinite looping
-skipFirstFrame Don't show the first frame on APNG-aware viewers.
Default: Always show first frame.
-silent Suppress console output.
Default: Some assembling information is printed.
-version Print version.
Example usage 1:
java -jar japng.jar -out test1.png -frames 1.png, 2.png, 3.png -display 500
Example usage 2:
java -jar japng.jar -out test2.png -frames framelist.txt
Contents of framelist.txt:
1.png; 1000; none; source
2.png; 1500; none; blend
3.png; 2000; none; blend