Bdtyktl

You can use ImageMagick package. Install it using the command:

sudo apt-get install imagemagick

Now you can create a gif from number of pictures(jpg) using:

convert -delay 20 -loop 0 *.jpg myimage.gif

To complete @Maythux answer:

To avoid generating a very large file, you can use -resize option:

In my case, I have 4608x3456 images and the generated gif was more than 300M for 32 images

convert -resize 20% -delay 20 -loop 0 *.jpg myimage.gif

or

convert -resize 768x576 -delay 20 -loop 0 *.jpg myimage.gif

Take care of *.jpg

*.jpg sucks a bit when dealing with numeric values, you may generate a gif with unsorted pics.

$ ls|cat

21-33-26_1.jpg

21-33-26_10.jpg   // <--- this one

21-33-26_2.jpg

21-33-26_3.jpg

21-33-26_4.jpg

21-33-26_5.jpg

21-33-26_6.jpg

21-33-26_7.jpg

21-33-26_8.jpg

21-33-26_9.jpg

21-33-28_1.jpg    // <--- should be here    

21-33-28_2.jpg

21-33-28_3.jpg

...

As the shots were taken very quickly (10/s) they all have the same modification time and you can't trick using ls -t for example. On ubuntu you can use ls -v instead, something like:

convert -resize 768x576 -delay 20 -loop 0 `ls -v` myimage.gif

Sorting numerically is quite tricky on Mac OS X though, I guess you'll need to build a custom script.

I don't have enough reputation to comment but instead of modifying file names you can use globbing to get your shell to expand file names

convert -resize 50% -delay 10 -loop 0 image_{0..99}.jpg output.gif

GIMP

You can easily do this with GIMP. First install it if it's not installed already with

sudo apt-get install gimp

Creating the gif

From GIMP go to File -> Open as Layers to open all the png's on their own layer.

From here you can perform edits on the layers and, once done, go to File -> Export As. From the dialog be sure to set the file type to GIF.

From there you will go to the GIF export options. Tick the 'As Animation' option and set the parameters as required.

You can use a program called convert included in the imagemagick package. It is command line driven, but very easy to use. Install it either through the software center, or go to a command prompt and type

sudo apt-get install imagemagick

Now to create the .gif.

convert -delay 100  -size 100x100 xc:SkyBlue 

          -page +5+10  balloon.gif   -page +35+30 medical.gif  

          -page +62+50 present.gif   -page +10+55 shading.gif  

          -loop 0  animation.gif

*Note the above example is straight from Image Magick Examples

ffmeg solution + test data

As of Ubuntu 18.10, ffpmeg 4.0.2-2, ImageMagick 6.9.10-8, I have found that ffmpeg is much faster and uses much less memory.

The simplest conversion command is:

ffmpeg 

  -framerate 60 

  -pattern_type glob 

  -i '*.png' 

  -r 15 

  -vf scale=512:-1 

  out.gif 

;

You can get my test data with:

wget -O opengl-rotating-triangle.zip https://github.com/cirosantilli/media/blob/master/opengl-rotating-triangle.zip?raw=true

unzip opengl-rotating-triangle.zip

cd opengl-rotating-triangle

The test data was generated with: https://stackoverflow.com/questions/3191978/how-to-use-glut-opengl-to-render-to-a-file/14324292#14324292 and contains 256 1024x1024 PNG images.

The important ffmpeg options I want to highlight are:

• -patter_type glob: convenient way to select images



• 
  

  -framerate 60: assume 60 FPS on input images, and output the same FPS.

  
  
  

  ffmpeg cannot know otherwise since no FPS data in images as in video formats.

  
  
  

  The 256 input frames take about 4 seconds to finish.

  
  
  

  -r 15: optional. Pick one every 4 images so reduce size (4 == 60 / 15).

  
  
  

  With it, identify out.gif says that the GIF contains only 64 frames.

  
  
  

  It still takes 4 seconds to play, so the delay is altered to make things match.

  
  



• -vf scale=512:-1: optional. Set the width, scale height proportionally, usually to reduce size and save space.

To get ImageMagick to work, I first had to modify its disk and memory limits at /etc/ImageMagick-6/policy.xml as explained at: https://superuser.com/questions/1178666/imagemagick-convert-quits-after-some-pages

See also:

• video from images: https://stackoverflow.com/questions/24961127/how-to-create-a-video-from-images-with-ffmpeg/37478183#37478183
  


• GIF from video: How to create an animated GIF from MP4 video via command line?
  

ImageMagick vs ffmpeg benchmark

I compared the commands:

/usr/bin/time -v convert *.png -deconstruct -delay 1.6 out-convert.gif

/usr/bin/time -v ffmpeg 

  -framerate 60 

  -pattern_type glob 

  -i '*.png' 

  out-ffmpeg.gif 

;

The commands were constructed to produce outputs that are as close as possible to make the comparison valid:

• /usr/bin/time -v: used to find the maximum memory usage as explained at: https://stackoverflow.com/questions/774556/peak-memory-usage-of-a-linux-unix-process



• 
  

  -deconstruct: GIF images can contain just the minimal modified rectangle from the previous frame to make the GIF smaller.

  
  
  

  ffmpeg calculates those diffs by default, but ImageMagick does not, unless -deconstruct is used.

  
  
  

  You will basically want to use that option every time with ImageMagick.

  
  
  

  We can observe the difference with:

  
  
  

  identify out.gif
  
  

  
  
  

  With the compressed version, all frames have smaller sizes than the initial one, e.g.:

  
  
  

  out.gif[0] GIF 1024x1024 1024x1024+0+0 8-bit sRGB 256c 16.7865MiB 0.010u 0:00.010
  
  out.gif[1] GIF 516x516 1024x1024+252+257 8-bit sRGB 256c 16.7865MiB 0.010u 0:00.010
  
  out.gif[2] GIF 515x520 1024x1024+248+257 8-bit sRGB 256c 16.7865MiB 0.010u 0:00.010
  
  

  
  
  

  In this example, the second frame is only 516x516 instead of the full 1024x1024, and is placed at an offset of 252+257. It therefore contains just the middle triangle.

  
  
  

  See also: how can I resize an animated GIF file using ImageMagick?

  
  



• -delay: value that matches the 60FPS of ffmpeg. Should not matter for conversion performance, but I don't want to risk it.

The output GIFs have about the same size and look visually identical.

We get for ImageMagick:

Elapsed (wall clock) time (h:mm:ss or m:ss): 0:56.16

Maximum resident set size (kbytes): 2676856

and for ffmpeg:

Elapsed (wall clock) time (h:mm:ss or m:ss): 0:04.41

Maximum resident set size (kbytes): 97172

from which we see that:

• ImageMagick used 2.6Gb of RAM and took about 1 minute


• ffmpeg used 100Mb of RAM and took 4 seconds

Test hardware: Lenovo ThinkPad P51 laptop, Intel Core i7-7820HQ, 32GB(16+16) DDR4 2400MHz SODIMM, 512GB SSD PCIe TLC OPAL2.