Basic tools
Photoshop and GIMP are common tools for image processing.
For bulk image processing, ImageMagick is recommended if the actions to be performed are the same on each image.
Extracting images from PDF files
If the PDF file is not a scan, then typically the images can be extracted with the Linux command pdfimages. Example command: pdfimages -j foo.pdf bar
will extract to bar-000.jpg, bar-001.jpg, bar-002.jpg, etc. This will not work for vectorized images.
If the PDF file is a scan or the plots are vectorized, it can be opened in GIMP or Photoshop and you can select the part of the paper which you want and save it separately. For vectorized images, it might be better to extract the image in Inkscape or something similar.
If you want to convert all pages to images, you can use Ghostscript on Linux, e.g.: gs -SDEVICE=tiffg4 -r300x300 -sPAPERSIZE=letter -sOutputFile=directory/name_%04d.tif -dNOPAUSE -dBATCH -- file.pdf
will extract all pages of file.pdf at a resolution of 300 dpi to the folder named directory.
Extracting data from plot images
If you have extracted a plot and want data from it, tools like g3data and WebPlotDigitizer can be very useful (other options discussed here). These allow you to point and click to grab data points and save them as a spreadsheet.
Creating animated movies and gifs
Webm Movies
sudo apt-get install mjpegtools
sudo apt-get install vpx-tools
png2yuv -I p -f 24 -b 1 -n 1440 -j my_image_%05d.png > my_vid.yuv
Where:
-I p Non-interlaced.
-f 24 24 frames per second.
-b 1 Start with image number 1.
-n 1440 The number of images to process.
-j my_image_%05d.png The file name pattern. %05d is the expanded to 00001, 00002, ..., 01440. %03d would expand to 001, 002, etc.
> my_vid.yuv Send output to a file instead of dumping it to your console screen.
vpxenc --good --cpu-used=0 --auto-alt-ref=1 --lag-in-frames=16 --end-usage=vbr --passes=2 --threads=2 --target-bitrate=3000 -o my_vid.webm my_vid.yuv
Gifs
convert -delay 20 -loop 0 *.png mygif.gif
http://blog.ahfr.org/2008/03/making-animated-gifs-with-free-software.html